Display Device and Electronic Device

ABSTRACT

A display device having a biometric authentication function is provided. A highly convenient display device is provided. The display device includes a first substrate, a light guide plate, a plurality of first light-emitting elements, a second light-emitting element, and a plurality of light-receiving elements. The light guide plate includes a first portion having a first surface and a second portion having a second surface that connects with the first surface and has a different normal direction from the first surface. The first light-emitting elements and the light-receiving elements are provided between the first substrate and the light guide plate. The first light-emitting elements have a function of emitting first light through the light guide plate, and the second light-emitting element has a function of emitting second light to a side surface of the light guide plate. The light-receiving elements have a function of receiving the second light and converting the second light to an electric signal. The first light includes visible light, and the second light includes infrared light.

TECHNICAL FIELD

One embodiment of the present invention relates to a display device. Oneembodiment of the present invention relates to a display deviceincluding a light-emitting element and a light-receiving element. Oneembodiment of the present invention relates to a display device havingan authentication function. One embodiment of the present inventionrelates to a touch panel. One embodiment of the present inventionrelates to a system including a display device.

Note that one embodiment of the present invention is not limited to theabove technical field. Examples of the technical field of one embodimentof the present invention disclosed in this specification and the likeinclude a semiconductor device, a display device, a light-emittingdevice, a power storage device, a memory device, an electronic device, alighting device, an input device (e.g., a touch sensor), an input/outputdevice (e.g., a touch panel), a driving method thereof, and amanufacturing method thereof. A semiconductor device generally means adevice that can function by utilizing semiconductor characteristics.

BACKGROUND ART

In recent years, application of display devices to a variety of uses hasbeen expected. Examples of uses for a large display device include atelevision device for home use (also referred to as a TV or a televisionreceiver), digital signage, and a PID (Public Information Display). Inaddition, a smartphone and a tablet terminal including a touch panel arebeing developed as portable information terminals.

Light-emitting devices including light-emitting elements have beendeveloped, for example, as display devices. Light-emitting elements(also referred to as EL elements) utilizing an electroluminescence(hereinafter referred to as EL) phenomenon have features such as ease ofreduction in thickness and weight, high-speed response to an inputsignal, and driving with a direct-current low voltage source, and havebeen used in display devices. For example, Patent Document 1 discloses aflexible light-emitting device including an organic EL element.

REFERENCE [Patent Document]

-   [Patent Document 1] Japanese Published Patent Application No.    2014-197522

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

An object of one embodiment of the present invention is to provide adisplay device having a photosensing function. Another object is toprovide a display device having a biometric authentication functiontypified by fingerprint authentication. Another object is to provide adisplay device having both a touch panel function and a biometricauthentication function. Another object is to provide a highlyconvenient display device. Another object is to provide amultifunctional display device. Another object is to provide a displaydevice having a novel structure.

Another object of one embodiment of the present invention is to providea display device having a function of obtaining user's healthconditions. Another object is to provide a display device which canmanage user's health.

Note that the description of these objects does not preclude theexistence of other objects. One embodiment of the present invention doesnot have to achieve all of these objects. Objects other than these canbe derived from the description of the specification, the drawings, theclaims, and the like.

Means for Solving the Problems

One embodiment of the present invention is a display device including afirst substrate, a light guide plate, a plurality of firstlight-emitting elements, a second light-emitting element, and aplurality of light-receiving elements. The light guide plate includes afirst portion having a first surface and a second portion having asecond surface that connects with the first surface and has a differentnormal direction from the first surface. An area of the second surfaceis smaller than an area of the first surface. The first substrateincludes a third portion provided along the first portion of the lightguide plate and a fourth portion provided along the second portion. Thefirst light-emitting elements and the light-receiving elements areprovided between the first substrate and the light guide plate. Thefirst light-emitting elements have a function of emitting first lightthrough the light guide plate, and the second light-emitting element hasa function of emitting second light to a side surface of the light guideplate. The light-receiving elements have a function of receiving thesecond light and converting the second light to an electric signal. Inaddition, the first light includes visible light, and the second lightincludes infrared light.

In the above, the first surface and the second surface each preferablyhave a flat surface. In addition, the light guide plate preferablyincludes a curved portion between the first portion and the secondportion. Furthermore, an angle formed between the first surface and thesecond surface is preferably greater than 0 degrees and less than orequal to 90 degrees.

In the above, the second surface preferably includes a curved surface.In addition, the first portion and the second portion are preferablyprovided to connect with each other in the light guide plate. In thiscase, it is further preferable that the second surface include thecurved surface curved at an angle of greater than or equal to 90 degreesand less than or equal to 180 degrees.

In the above, the second light-emitting element is preferably providedso as to emit the second light to the side surface positioned in an endportion on the first portion side of the light guide plate.Alternatively, the second light-emitting element is preferably providedso as to emit the second light to the side surface positioned in an endportion on the second portion side of the light guide plate.

In the above, the first light-emitting elements preferably include afirst pixel electrode, a light-emitting layer, and a first electrode.The light-receiving elements include a second pixel electrode, an activelayer, and a second electrode. The light-emitting layer and the activelayer include different organic compounds from each other. The firstpixel electrode and the second pixel electrode are provided over a samesurface.

Alternatively, in the above, the first light-emitting elementspreferably include a first pixel electrode, a light-emitting layer, anda common electrode. The light-receiving elements include a second pixelelectrode, an active layer, and the common electrode. The light-emittinglayer and the active layer include different organic compounds from eachother. The first pixel electrode and the second pixel electrode areprovided over a same surface. The common electrode includes a portionoverlapping with the first pixel electrode with the light-emitting layertherebetween and a portion overlapping with the second pixel electrodewith the active layer therebetween.

Alternatively, in the above, the first light-emitting elementspreferably include a first pixel electrode, a common layer, alight-emitting layer, and a common electrode. In this case, thelight-receiving elements include a second pixel electrode, the commonlayer, an active layer, and the common electrode. The light-emittinglayer and the active layer include different organic compounds from eachother. The first pixel electrode and the second pixel electrode areprovided over a same surface. The common layer includes a portionoverlapping with the first pixel electrode and the light-emitting layerand a portion overlapping with the second pixel electrode and the activelayer. The common electrode includes a portion overlapping with thefirst pixel electrode with the common layer and the light-emitting layertherebetween and a portion overlapping with the second pixel electrodewith the common layer and the active layer therebetween.

One embodiment of the present invention is an electronic deviceincluding a housing, a display portion, and an arithmetic portion. Thedisplay portion includes a first portion provided along a surface of thehousing and a second portion provided along another surface of thehousing. The second portion includes a region whose surface has adifferent normal direction from a surface of the first portion. Thesecond portion includes a light-receiving element. In addition, thearithmetic portion has a function of executing, when a finger of a usertouches the second portion, fingerprint authentication with an image ofa fingerprint obtained by image capturing of light reflected by thefinger by the light-receiving element.

Effect of the Invention

With one embodiment of the present invention, a display device having aphotosensing function can be provided. A display device having abiometric authentication function typified by fingerprint authenticationcan be provided. A display device having both a touch panel function anda biometric authentication function can be provided. A highly convenientdisplay device can be provided. A multifunctional display device can beprovided. A display device having a novel structure can be provided.

With one embodiment of the present invention, a display device having afunction of obtaining user's health conditions can be provided. Adisplay device which can manage user's health can be provided.

Note that the description of these effects does not preclude theexistence of other effects. One embodiment of the present invention doesnot have to have all of these effects. Effects other than these can bederived from the description of the specification, the drawings, theclaims, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A, FIG. 1B, FIG. 1D, and FIG. 1F to FIG. 1H are diagramsillustrating structure examples of a display device. FIG. 1C and FIG. 1Eare diagrams illustrating examples of images.

FIG. 2A to FIG. 2C are diagrams illustrating a structure example of adisplay device.

FIG. 3A to FIG. 3D are diagrams illustrating structure examples of adisplay device.

FIG. 4A to FIG. 4C are diagrams illustrating structure examples of adisplay device.

FIG. 5A to FIG. 5C are diagrams illustrating structure examples of adisplay device.

FIG. 6A to FIG. 6C are diagrams illustrating structure examples of adisplay device.

FIG. 7A to FIG. 7C are diagrams illustrating structure examples of adisplay device.

FIG. 8A and FIG. 8B are diagrams illustrating structure examples of adisplay device.

FIG. 9A to FIG. 9C are diagrams illustrating structure examples of adisplay device.

FIG. 10 is a diagram illustrating a structure example of a displaydevice.

FIG. 11 is a diagram illustrating a structure example of a displaydevice.

FIG. 12A and FIG. 12B are diagrams illustrating structure examples of adisplay device.

FIG. 13A and FIG. 13B are diagrams illustrating structure examples of adisplay device.

FIG. 14 is a diagram illustrating a structure example of a displaydevice.

FIG. 15A to FIG. 15C are diagrams illustrating a structure example of anelectronic device.

FIG. 16 is a diagram illustrating a structure example of an electronicdevice.

FIG. 17 is a diagram illustrating a structure example of an electronicdevice.

FIG. 18A and FIG. 18B are diagrams illustrating a structure example ofan electronic device.

FIG. 19 is a diagram illustrating a structure example of a system.

FIG. 20 is a flow chart showing a system operation method.

FIG. 21A and FIG. 21B are diagrams illustrating structure examples ofpixel circuits.

FIG. 22A and FIG. 22B are diagrams illustrating a structure example ofan electronic device.

FIG. 23A to FIG. 23D are diagrams illustrating structure examples ofelectronic devices.

FIG. 24A to FIG. 24F are diagrams illustrating structure examples ofelectronic devices.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments will be described with reference to thedrawings. Note that the embodiments can be implemented in many differentmodes, and it will be readily understood by those skilled in the artthat modes and details thereof can be changed in various ways withoutdeparting from the spirit and scope thereof. Thus, the present inventionshould not be construed as being limited to the following description ofthe embodiments.

Note that in structures of the invention described below, the sameportions or portions having similar functions are denoted by the samereference numerals in different drawings, and a description thereof isnot repeated. Furthermore, the same hatch pattern is used for theportions having similar functions, and the portions are not especiallydenoted by reference numerals in some cases.

Note that in each drawing described in this specification, the size, thelayer thickness, or the region of each component is exaggerated forclarity in some cases. Therefore, they are not limited to theillustrated scale.

Note that in this specification and the like, the ordinal numbers suchas “first” and “second” are used in order to avoid confusion amongcomponents and do not limit the number.

In this specification and the like, a display panel that is oneembodiment of a display device has a function of displaying (outputting)an image or the like on (to) a display surface. Therefore, the displaypanel is one embodiment of an output device.

In this specification and the like, a substrate of a display panel towhich a connector such as an FPC (Flexible Printed Circuit) or a TCP(Tape Carrier Package) is attached, or a substrate on which an IC ismounted by a COG (Chip On Glass) method or the like is referred to as adisplay panel module, a display module, or simply a display panel or thelike in some cases.

Note that in this specification and the like, a touch panel that is oneembodiment of a display device has a function of displaying an image orthe like on a display surface and a function of a touch sensor thatsenses the contact, press, approach, or the like of a sensing targetsuch as a finger or a stylus with or to the display surface. Thus, thetouch panel is one embodiment of an input/output device.

A touch panel can also be referred to as, for example, a display panel(or a display device) with a touch sensor, or a display panel (or adisplay device) having a touch sensor function. A touch panel caninclude a display panel and a touch sensor panel. Alternatively, a touchpanel can have a function of a touch sensor in the display panel or onthe surface of the display panel.

In this specification and the like, a substrate of a touch panel onwhich a connector and an IC are mounted is referred to as a touch panelmodule, a display module, or simply a touch panel or the like in somecases.

Embodiment 1

In this embodiment, structure examples of a display device of oneembodiment of the present invention are described.

The display device of one embodiment of the present invention includes adisplay element that exhibits visible light and a light-receivingelement (also referred to as a light-receiving device) that receivesinfrared light. The display element is preferably a light-emittingelement (also referred to as a first light-emitting element (device)).Furthermore, the light-receiving element is preferably a photoelectricconversion element.

The display device includes a substrate (also referred to as a firstsubstrate) and a light guide plate. The display element and thelight-receiving element are arranged between the first substrate and thelight guide plate. In addition, the display device includes alight-emitting element (also referred to as a second light-emittingelement) that emits infrared light to a side surface of the light guideplate.

Visible light is emitted from the display element to the outside throughthe light guide plate. A plurality of such display elements arranged ina matrix are included in the display device, so that an image can bedisplayed.

Infrared light incident on the side surface of the light guide platediffuses while repeating total reflection inside the light guide plate.Here, when an object touches a surface of the light guide plate (asurface opposite to the surface on the first substrate side), infraredlight is scattered at an interface between the light guide plate and theobject, and part of the scattered light enters the light-receivingelement. When receiving infrared light, the light-receiving element canconvert the light into an electric signal in accordance with theintensity of the infrared light and output the electric signal. In thecase where a plurality of light-receiving elements arranged in a matrixare included in the display device, positional data, shape, or the likeof the object that touches the light guide plate can be sensed. That is,the display device can function as an image sensor panel, a touch sensorpanel, or the like.

Furthermore, using infrared light, which cannot be seen by the user, asthe light that diffuses inside the light guide plate enables imagecapturing or sensing by the light-receiving element without a reductionin visibility of a displayed image.

Light emitted by the second light-emitting element preferably includesinfrared light, and further preferably includes near-infrared light. Inparticular, near-infrared light having one or more peaks in the range ofa wavelength greater than or equal to 700 nm and less than or equal to2500 nm can be favorably used. In particular, the use of light havingone or more peaks in the range of a wavelength greater than or equal to750 nm and less than or equal to 1000 nm is preferable because itpermits an extensive choice of a material used for an active layer ofthe light-receiving element.

When a fingertip touches the light guide plate of the display device, animage of the shape of a fingerprint can be captured. A fingerprint has adepression and a projection. When a finger touches the light guideplate, infrared light is likely to be scattered by the projection of thefingerprint touching the light guide plate. Therefore, the intensity ofinfrared light that enters the light-receiving element overlapping withthe projection of the fingerprint is high, and the intensity of infraredlight that enters the light-receiving element overlapping with thedepression is low. Utilizing this, a fingerprint image can be captured.A device including the display device of one embodiment of the presentinvention can perform fingerprint authentication, which is a kind ofbiometric authentication, by utilizing a captured fingerprint image.

In addition, the display device can also capture an image of a bloodvessel, especially a vein of a finger, a hand, or the like. For example,light having a wavelength of 760 nm and its vicinity (near-infraredlight) is not absorbed by reduced hemoglobin in a vein, so that theposition of the vein can be sensed by making an image from reflectedlight from a palm, a finger, or the like that is received by thelight-receiving element. A device including the display device of oneembodiment of the present invention can perform vein authentication,which is a kind of biometric authentication, by utilizing a capturedvein image.

In addition, the device including the display device of one embodimentof the present invention can also perform fingerprint authentication andvein authentication at the same time. Thus, biometric authenticationwith higher level of security can be executed without increasing thenumber of components.

Here, the light guide plate may be in a flat plate shape or may bepartly or entirely curved. The light guide plate is particularlypreferably provided with, adjacent to a portion positioned on a maindisplay surface (also referred to as a first portion), a second portionwhose surface has a different normal direction from that of the firstportion. The second portion is the portion positioned on a displaysurface (also referred to as a sub display surface) that is tilted awayfrom the main display surface. In this case, the substrate is providedalong the light guide plate. In other words, the display elements andthe light-receiving elements are each provided along the first portionand the second portion. Note that two second portions may be provided sothat the first portion is sandwiched between the second portions.

A display device which includes the sub display surface that is adjacentto the main display surface and tilted away from the main displaysurface can be favorably used in an electronic device functioning as aportable information terminal. The display device is preferably mountedin the electronic device so that the sub display surface is positionedin a portion that is naturally touched by a finger when the user graspsthe electronic device with one hand. Accordingly, an authenticationoperation with a finger that touches the sub display surface can beexecuted when the user performs an action of taking out the electronicdevice from a bag, a pocket, or the like. Therefore, at the point whenthe user takes out the electronic device and turns the eyes to thescreen, the authentication has already been finished and the user haslogged in the electronic device; thus, the user can start using theelectronic device immediately without waiting for the authenticationsubstantially.

Here, the light-receiving element is preferably an element that canreceive not only infrared light but also visible light. Accordingly,light emitted by the first light-emitting element is reflected by auser's finger and the reflected light is received by the light-receivingelement, so that an image of the shape of a fingerprint can be captured.Furthermore, an image of the shape of a vein can be captured withinfrared light. Accordingly, both fingerprint authentication and veinauthentication can be executed in one display device. Moreover,fingerprint image capturing and vein image capturing may be executedeither at different timings or at the same time. In the case wherefingerprint image capturing and vein image capturing are performed atthe same time, image data including both data on the shape of afingerprint and data on the shape of a vein can be obtained, so thatbiometric authentication with higher accuracy can be achieved.

The display device of one embodiment of the present invention may have afunction of sensing user's health conditions. For example, by utilizingchanges in reflectance and transmittance with respect to visible lightand infrared light in accordance with a change in blood oxygensaturation, temporal modulation of the oxygen saturation is obtained,from which a heart rate can be measured. Furthermore, a glucoseconcentration in dermis, a neutral fat concentration in the blood, orthe like can also be measured with infrared light or visible light. Thedevice including the display device of one embodiment of the presentinvention can be used as a health care device capable of obtaining indexdata on user's health conditions.

Furthermore, a second substrate may be provided between the firstsubstrate and the light guide plate. As the second substrate, a sealingsubstrate for sealing the light-emitting element, a protective film, orthe like can be used, for example. In addition, a resin layer may beprovided between the first substrate and the light guide plate to attachthe first substrate and the light guide plate to each other. Using, asthe resin layer, a material having a lower refractive index with respectto infrared light emitted by the second light-emitting element than thelight guide plate can inhibit infrared light that diffuses inside thelight guide plate from reaching the resin layer side and entering thelight-receiving element.

A conductive layer that transmits visible light may be provided incontact with the light guide plate. In this case, it is preferable touse, as the conductive layer, a material having a higher refractiveindex with respect to infrared light emitted by the secondlight-emitting element than the light guide plate in order that theinfrared light can also diffuse into the conductive layer. Theconductive layer provided in contact with the light guide plate can beused as an electrostatic shielding film, for example. The conductivelayer can also function as an electrode of a capacitive touch sensor,for example. Furthermore, the conductive layer can also be used aselectrodes or wirings of a variety of sensors or functional elements.

Here, in the case where a light-emitting element is used as the displayelement, an EL element such as an OLED (Organic Light Emitting Diode) ora QLED (Quantum-dot Light Emitting Diode) is preferably used. As alight-emitting substance included in the EL element, a substance whichemits fluorescence (a fluorescent material), a substance which emitsphosphorescence (a phosphorescent material), a substance which exhibitsthermally activated delayed fluorescence (a thermally activated delayedfluorescent (TADF) material), an inorganic compound (e.g., a quantum dotmaterial), and the like can be given. Alternatively, an LED (alight-emitting diode) such as a micro-LED can be used as thelight-emitting element.

As the light-receiving element, a pn photodiode or a pin photodiode canbe used, for example. The light-receiving element functions as aphotoelectric conversion element that senses light incident on thelight-receiving element and generates charge. The amount of generatedcharge in the photoelectric conversion element is determined dependingon the amount of incident light. It is particularly preferable to use anorganic photodiode including a layer containing an organic compound asthe light-receiving element. An organic photodiode, which is easily madethin, lightweight, and large in area and has a high degree of freedomfor shape and design, can be used in a variety of display devices.

The light-emitting element can have a stacked-layer structure includinga light-emitting layer between a pair of electrodes, for example. Thelight-receiving element can have a stacked-layer structure including anactive layer between a pair of electrodes. A semiconductor material canbe used for the active layer of the light-receiving element. Forexample, an inorganic semiconductor material such as silicon can beused.

An organic compound is preferably used for the active layer of thelight-receiving element. In that case, one electrode of thelight-emitting element and one electrode of the light-receiving element(the electrodes are also referred to as pixel electrodes) are preferablyprovided on the same plane. It is further preferable that the otherelectrode of the light-emitting element and the other electrode of thelight-receiving element be an electrode (also referred to as a commonelectrode) formed using one continuous conductive layer. It is stillfurther preferable that the light-emitting element and thelight-receiving element include a common layer. Thus, the manufacturingprocess of the light-emitting element and the light-receiving elementcan be simplified, so that the manufacturing cost can be reduced and themanufacturing yield can be increased.

More specific examples are described below with reference to drawings.

Structure Example 1 of Display Device Structure Example

A schematic diagram of a display device 50 is illustrated in FIG. 1A.The display device 50 includes a substrate 51, a substrate 52, a lightguide plate 59, a light-receiving element 53, a light-emitting element54, a light-emitting element 57R, a light-emitting element 57G, alight-emitting element 57B, a functional layer 55, and the like.

The light-emitting element 57R, the light-emitting element 57G, thelight-emitting element 57B, and the light-receiving element 53 areprovided between the substrate 51 and the substrate 52.

The light-emitting element 57R, the light-emitting element 57G, and thelight-emitting element 57B emit red (R) light, green (G) light, and blue(B) light, respectively.

The display device 50 includes a plurality of pixels arranged in amatrix. One pixel includes one or more subpixels. One subpixel includesone light-emitting element. For example, the pixel can have a structureincluding three subpixels (e.g., three colors of R, G, and B or threecolors of yellow (Y), cyan (C), and magenta (M)) or four subpixels(e.g., four colors of R, G, B, and white (W) or four colors of R, G, B,and Y). The pixel further includes the light-receiving element 53. Thelight-receiving element 53 may be provided in all the pixels or may beprovided in some of the pixels. In addition, one pixel may include aplurality of light-receiving elements 53.

The light guide plate 59 is provided over the substrate 52. As the lightguide plate 59, a material having a high light-transmitting propertywith respect to visible light and infrared light is preferably used. Forexample, a material whose light-transmitting property with respect toboth light having a wavelength of 600 nm and light having a wavelengthof 800 nm is 80% or more, preferably 85% or more, further preferably 90%or more, still further preferably 95% or more and 100% or less can beused.

Furthermore, as the light guide plate 59, a material having a highrefractive index with respect to light emitted by the light-emittingelement 54 is preferably used. For example, a material whose refractiveindex with respect to light having a wavelength of 800 nm is higher thanor equal to 1.2 and lower than or equal to 2.5, preferably higher thanor equal to 1.3 and lower than or equal to 2.0, further preferablyhigher than or equal to 1.4 and lower than or equal to 1.8 can be used.

Moreover, it is preferable that the light guide plate 59 and thesubstrate 52 be provided in contact with each other or be attached toeach other with a resin layer or the like. In this case, the substrate52 or the resin layer in contact with the light guide plate 59preferably has a lower refractive index with respect to light in awavelength range from 800 nm to 1000 nm than the light guide plate 59,in at least a portion in contact with the light guide plate 59.

The light-emitting element 54 is provided in the vicinity of a sidesurface of the light guide plate 59. The light-emitting element 54 canemit infrared light IR to the side surface of the light guide plate 59.As the light-emitting element 54, a light-emitting element that can emitinfrared light including light having the above-described wavelength canbe used. As the light-emitting element 54, an EL element such as an OLEDor a QLED or an LED can be used. A plurality of light-emitting elements54 may be provided along the side surface of the light guide plate 59.

FIG. 1A illustrates a finger 60 touching a surface of the light guideplate 59. Part of the infrared light IR that diffuses inside the lightguide plate 59 is reflected or scattered by a contact portion betweenthe light guide plate 59 and the finger 60. Then, part of scatteredlight IR(r) of the infrared light IR enters the light-receiving element53, and the contact of the finger 60 with the light guide plate 59 canbe sensed. That is, the display device 50 can function as a touch panel.

The functional layer 55 includes a circuit that drives thelight-emitting element 57R, the light-emitting element 57G, and thelight-emitting element 57B and a circuit that drives the light-receivingelement 53. The functional layer 55 is provided with a switch, atransistor, a capacitor, a wiring, and the like. Note that in the casewhere the light-emitting element 57R, the light-emitting element 57G,the light-emitting element 57B, and the light-receiving element 53 aredriven by a passive-matrix method, a structure not provided with aswitch or a transistor may be employed.

The display device 50 may have a function of sensing a fingerprint ofthe finger 60. FIG. 1B schematically illustrates an enlarged view of thecontact portion in a state where the finger 60 touches the light guideplate 59. FIG. 1B illustrates light-emitting elements 57 and thelight-receiving elements 53 that are alternately arranged.

The fingerprint of the finger 60 is formed of depressions andprojections. Therefore, as illustrated in FIG. 1B, the projections ofthe fingerprint touch the light guide plate 59, and the scattered lightTR(r) is generated at the contact surfaces.

As illustrated in FIG. 1B, the scattered light TR(r), which is scatteredat the contact surface between the finger 60 and the light guide plate59, can be scattered isotropically from the contact surface. In theintensity distribution of the scattered light TR(r), the intensity in analmost perpendicular direction to the contact surface is the highest,and the intensity becomes lower as the angle becomes larger to anoblique direction. Thus, the intensity of light received by thelight-receiving element 53 positioned directly below the contact surface(i.e., overlapping with the contact surface) is the highest. Of thescattered light TR(r), light at greater than or equal to a predeterminedscattering angle is totally reflected at the other surface (a surfaceopposite to the contact surface) of the light guide plate 59 and doesnot reach the light-receiving element 53 side, as illustrated in FIG.1B.

In the case where an arrangement interval between the light-receivingelements 53 is smaller than a distance between two projections of afingerprint, preferably a distance between a depression and a projectionadjacent to each other, a clear fingerprint image can be obtained. Thedistance between a depression and a projection of a human's fingerprintis approximately 200 μm; thus, the arrangement interval between thelight-receiving elements 53 is, for example, less than or equal to 400μm, preferably less than or equal to 200 μm, further preferably lessthan or equal to 150 μm, still further preferably less than or equal to100 μm, even still further preferably less than or equal to 50 μm andgreater than or equal to 1 μm, preferably greater than or equal to 10μm, further preferably greater than or equal to 20 μm.

At the contact surface between the finger 60 and the light guide plate59, not only scattering but also reflection of the infrared light IRmight occur. The reflection angle of the reflected light changesdepending on the incident angle of the infrared light IR; therefore, theintensity distribution might differ between the reflected light and thescattered light IR(r). However, in the case where the distance betweenthe contact surface and the light-receiving element 53 is short enoughwith respect to the arrangement interval between the light-receivingelements 53, the difference in intensity distribution between thescattered light IR(r) and the reflected light is negligible and hardlyinfluences the clarity of a captured image.

FIG. 1C illustrates an example of a fingerprint image captured with thedisplay device 50. In an image-capturing range 63 in FIG. 1C, theoutline of the finger 60 is indicated by a dashed line and the outlineof a contact portion 61 is indicated by a dashed-dotted line. In thecontact portion 61, a high-contrast image of a fingerprint 62 can becaptured owing to a difference in the amount of light incident on thelight-receiving elements 53.

The display device 50 can also function as a touch panel or a pentablet. FIG. 1D shows a state in which a tip of a stylus 65 slides in adirection indicated by a dashed arrow while the tip of the stylus 65touches the light guide plate 59.

As shown in FIG. 1D, when the scattered light IR(r) scattered by thecontact surface between the tip of the stylus 65 and the light guideplate 59 enters the light-receiving element 53 that is positioned in aportion overlapping with the scattering surface, the position of the tipof the stylus 65 can be sensed with high accuracy.

FIG. 1E illustrates an example of a path 66 of the stylus 65 that issensed by the display device 50. The display device 50 can sense theposition of a sensing target, such as the stylus 65, with high positionaccuracy, so that high-definition drawing can be performed using adrawing application or the like.

Here, FIG. 1F to FIG. 1H illustrate examples of a pixel 30 that can beused in the display device 50.

The pixel 30 illustrated in FIG. 1F and FIG. 1G includes a red (R) pixel31R, a green (G) pixel 31G, and a blue (B) pixel 31B, which eachfunction as a subpixel for display, and a pixel 32 functioning as alight-receiving pixel. The pixel 31R, the pixel 31G, and the pixel 31Binclude one or more light-emitting elements 57R, one or morelight-emitting elements 57G, and one or more light-emitting elements57B, respectively. The pixel 32 includes one or more light-receivingelements 53.

FIG. 1F illustrates an example in which three subpixels and the pixel 32are provided in a matrix of 2×2. FIG. 1G illustrates an example in whichthe three subpixels and the pixel 32 are arranged in a line.

The pixel 30 illustrated in FIG. 1H is an example including a white (W)pixel 31W. The pixel 31W includes one or more white light-emittingelements. Here, the four subpixels are laterally arranged in a line andthe pixel 32 is provided below the four subpixels.

Note that the pixel structure is not limited to the above structure, anda variety of arrangement methods can be employed.

Application Example

An example of a case where an image of a user's fingerprint and an imageof a user's blood vessel are captured is described below. The displaydevice can execute a mode of performing image capturing of a fingerprintwith the use of visible light, a mode of performing image capturing of ablood vessel with the use of infrared light, and a mode of performingimage capturing of a fingerprint and a blood vessel as one image withthe use of both visible light and infrared light.

FIG. 2A illustrates a state in which image capturing of a fingerprint isperformed with the use of visible light. In this case, thelight-emitting element 54 is not made to emit light, and thelight-emitting element 57G is made to emit light. Green light G emittedby the light-emitting element 57G is delivered to a surface of thefinger 60, and part of the light is reflected or scattered. Then, partof the scattered light G(r) enters the light-receiving element 53. Sincethe light-receiving elements 53 are arranged in a matrix, an image ofthe fingerprint of the finger 60 can be obtained by mapping theintensity of the scattered light G(r) sensed by each light-receivingelement 53.

FIG. 2B illustrates a state in which image capturing of a blood vesselis performed with the use of infrared light. In this case, thelight-emitting element 57R, the light-emitting element 57G, and thelight-emitting element 57B are not made to emit light; and thelight-emitting element 54 is made to emit light. Part of the infraredlight IR which diffuses inside the light guide plate 59 passes throughthe contact portion between the light guide plate 59 and the finger 60and reaches the inside of the finger 60. Then, part of the infraredlight IR is reflected or scattered by a blood vessel 67 positionedinside the finger 60, and the reflected light TR(r) enters thelight-receiving element 53. By mapping the intensity of the incidentlight TR(r) in a manner similar to that described above, an image of theblood vessel 67 can be obtained.

FIG. 2C illustrates a state in which image capturing with the use ofvisible light and image capturing with the use of infrared light areconcurrently performed. The scattered light G(r) and the scattered lightTR(r) enter the light-receiving element 53. By performing mapping in amanner similar to that described above without discriminating betweenthe intensities of two kinds of scattered light obtained by thelight-receiving element 53, an image reflecting the shape of thefingerprint and the shape of the blood vessel 67 can be obtained.

Here, the blood vessel 67 includes a vein and an artery. In the case ofobtaining an image of a vein inside the finger 60, the image can be usedfor vein authentication.

Furthermore, the reflectance with respect to infrared light or visiblelight of an artery (arteriole) inside the finger 60 changes inaccordance with a change in blood oxygen saturation. By obtaining thischange over time, i.e., temporal modulation of blood oxygen saturation,data on the pulse wave can be obtained. Thus, the user's heart rate canbe measured. Although an example in which data on the pulse wave isobtained with the infrared light IR is described here, measurement ispossible with the use of visible light.

The data obtained by capturing images of the inside of the finger 60 andthe blood vessel 67 can be oxygen saturation in blood, the neutral fatconcentration in blood, the glucose concentration in blood or dermis,and the like. The blood sugar level can be estimated from the glucoseconcentration. This kind of data is an indicator of user's healthconditions; changes of daily health conditions can be monitored bymeasuring the data once or more a day. A device including the displaydevice of one embodiment of the present invention can obtain biologicaldata at the same time when the device executes fingerprintauthentication or vein authentication; accordingly, management of user'shealth is unconsciously possible without troubling the user.

Note that although the light-emitting element 57G that emits green lightis used as a light source of visible light in the above description,without limitation thereto, the light-emitting element 57R or thelight-emitting element 57B may be used or two or more of the threelight-emitting elements may be used. As the light-emitting element 54,as well as one kind of light-emitting element, a plurality oflight-emitting elements that emit infrared light with differentwavelengths or a light-emitting element that emits continuous-wavelengthinfrared light may be used. As a light source used for fingerprintauthentication, vein authentication, or obtainment of biological data, alight source that emits light of a wavelength appropriate for the usescan be selected and used.

Structure Example 2 of Display Device

A structure example of a display device whose structure is partlydifferent from that of the above-described structure example isdescribed below.

Structure Example 2-1

A display device 50 a illustrated in FIG. 3A is chiefly different fromthe above-described display device 50 in including a resin layer 71instead of the substrate 52.

For the resin layer 71, a material that transmits visible light can beused. Furthermore, the resin layer 71 may have a function of attachingthe substrate 51 and the light guide plate 59.

The resin layer 71 is provided in contact with the light guide plate 59.Here, the refractive index with respect to light in a wavelength rangefrom 800 nm to 1000 nm of at least a portion in contact with the lightguide plate 59 of the resin layer 71 is preferably lower than that ofthe light guide plate 59. Thus, as illustrated in FIG. 3A, the infraredlight IR can be totally reflected at an interface between the lightguide plate 59 and the resin layer 71.

Structure Example 2-2

A display device 50 b illustrated in FIG. 3B is chiefly different fromthe above-described display device 50 a in including a conductive layer72.

The conductive layer 72 is provided in contact with the light guideplate 59. Here, an example in which the conductive layer 72 ispositioned between the light guide plate 59 and the resin layer 71 isillustrated.

By being applied with a predetermined potential, the conductive layer 72can function as an electrostatic shielding film. The conductive layer 72can favorably prevent electric noise input from the outside through thelight guide plate 59 from reaching a circuit or the like included in thedisplay device 50 b.

Furthermore, the conductive layer 72 can also function as an electrodeof a sensor element such as a touch sensor. The conductive layer 72 isparticularly preferably used as an electrode of a capacitive touchsensor.

For the conductive layer 72, a conductive material that transmitsvisible light can be used. Furthermore, a conductive material thattransmits the infrared light IR, which is emitted by the light-emittingelement 54, can be favorably used for the conductive layer 72.

A conductive material having a higher refractive index with respect tolight in a wavelength range from 800 nm to 1000 nm than the light guideplate 59 is preferably used for at least a portion in contact with thelight guide plate 59 of the conductive layer 72. Thus, as illustrated inFIG. 3B, the infrared light IR can diffuse into not only the light guideplate 59 but also the conductive layer 72. In addition, because therefractive index with respect to light in the above-described wavelengthrange of the conductive layer 72 is higher than that of the resin layer71, the infrared light IR can be totally reflected at an interfacebetween the conductive layer 72 and the resin layer 71.

Although an example including the resin layer 71 is described here, astructure including the substrate 52 may be used as well.

Structure Example 2-3

A display device 50 c illustrated in FIG. 3C is an example in which thelight-emitting element 57R and the like are provided on a surfacedifferent from a surface on which the light-receiving element 53 isprovided. The display device 50 c includes a substrate 51 a, a substrate51 b, a functional layer 55 a, a functional layer 55 b, and the like.

The functional layer 55 a is a layer including a circuit that drives thelight-emitting element 57R and the like and is provided over thesubstrate 51 a. Furthermore, the functional layer 55 b is a layerincluding a circuit that drives the light-receiving element 53 and isprovided over the substrate 51 b. The substrate 51 a and the substrate51 b are preferably fixed with an adhesive layer (not illustrated) orthe like.

In this case, an inorganic semiconductor material such as silicon can beused for an active layer included in the light-receiving element 53. Inthis case, single crystal silicon, polycrystalline silicon, amorphoussilicon, or the like can be selected and used for the active layer inaccordance with the wavelength of the infrared light IR. Note that anexample in which the functional layer 55 b and the light-receivingelement 53 are stacked over the substrate 51 b is described here; in thecase where a semiconductor substrate is used as the substrate 51 b, thesubstrate 51 b may form a part of the functional layer 55 b and a partof the light-receiving element 53.

Structure Example 2-4

A display device 50 d illustrated in FIG. 3D is chiefly different fromthe display device 50 c in that the light-emitting element 57R and thelike and the light-receiving element 53 are provided with the functionallayer 55 therebetween.

The inorganic semiconductor material described above, such as silicon,can be used for the active layer included in the light-receiving element53. Furthermore, in the case where a semiconductor substrate is used asthe substrate 51, the substrate 51 may form a part of the active layeror the like of the light-receiving element 53.

In the display device 50 c and the display device 50 d, a structure inwhich the resin layer 71 is provided instead of the substrate 52 may beused; or a structure including the conductive layer 72 may be used.

Structure Example of Light Guide Plate

The light guide plate that can be used in the display device of oneembodiment of the present invention is provided in a display portion ofan electronic device and can also serve as part of a housing functioningas a display surface or a touch surface, for example. In this case, thelight guide plate functions as a protective member that protects thelight-emitting elements, the light-receiving element, the functionallayer, and the like. For example, tempered glass, a flexible film, orthe like can be used as the light guide plate.

FIG. 4A illustrates a structure example of a display device 50 e. Thedisplay device 50 e has a structure provided with alight guide plate 59a over the substrate 52. FIG. 4A is an example including the light guideplate 59 a having a flat-plate shape.

The light-emitting element 54 that emits the infrared light IR isprovided along one end portion of the light guide plate 59 a. Inaddition, a reflective layer 58 is provided on the side opposite to theside provided with the light-emitting element 54 of the light guideplate 59 a. The reflective layer 58 has a function of reflecting theinfrared light IR. With the reflective layer 58, the intensitydistribution of the infrared light IR that diffuses inside the lightguide plate 59 a can be made uniform.

FIG. 4B illustrates a structure example of a display device 50 fincluding a light guide plate 59 b whose end portions are both curved.

In a manner similar to that of the light guide plate 59 a, the lightguide plate 59 b is provided with the light-emitting element 54 alongits one end portion and is provided with the reflective layer 58 alongthe other end portion. The infrared light IR diffuses inside the lightguide plate 59 b.

The structure in which both end portions of the light guide plate 59 bare curved and the light-emitting element 54 and the reflective layer 58are provided along the end portions is preferable in order to reduce thearea of a non-display region (also referred to as a bezel) thatsurrounds a display portion of an electronic device using the displaydevice 50 f.

In some cases, part of the infrared light IR is not totally reflectedand is delivered to the outside in the curved portions of the lightguide plate 59 b, and the intensity of the infrared light IR thatdiffuses inside the light guide plate 59 b might be decreased. However,for example, adequately thinning the light guide plate 59 b can increasethe total reflection rate of the infrared light IR. For example, thethickness of the light guide plate 59 b is less than or equal to 2 mm,preferably less than or equal to 1 mm, further preferably less than orequal to 0.8 mm, still further preferably less than or equal to 0.7 mm,and more than or equal to 10 μm, preferably more than or equal to 30 μm,further preferably more than or equal to 50 μm, whereby the reduction inthe intensity of the infrared light IR in the light guide plate 59 b canbe inhibited.

FIG. 4C illustrates a structure example of a display device 50 g inwhich the substrate 51 and the like are provided so as to be curvedalong a light guide plate 59 c that is curved partly.

For the substrate 51, a flexible material can be used. In the case wherethe radii of curvature of the curved portions of the light guide plate59 c are sufficiently large, an inorganic insulating substrate such as aglass substrate can be used as the substrate 51. Furthermore, a materialincluding an organic resin or the like is preferably used for thesubstrate 51.

Moreover, FIG. 4C illustrates an example in which the substrate 51 andthe light guide plate 59 c are attached to each other with the resinlayer 71. In the case where the substrate 51 is provided along a curvedsurface of the light guide plate 59 c, such a structure in which thesubstrate 52 is not provided and attachment is performed with the resinlayer 71 is preferable to facilitate bonding between the substrate 51and the light guide plate 59 c. In addition to that, the distancebetween the light-receiving element 53 and the light guide plate 59 ccan be made small, producing synergistic effects such as higher accuracyof positional sensing and clear image capturing.

Although an example in which the light guide plate 59 c includes acurved portion and a flat portion is illustrated in FIG. 4C, the lightguide plate 59 c may have an entirely curved shape without including aflat portion.

FIG. 5A illustrates a structure example of a display device 50 h inwhich a light guide plate 59 d is curved 180 degrees in its end portion.The display device 50 h includes a curved portion 40.

A portion other than the curved portion 40 of the display device 50 hcan be referred to as a first display portion functioning as a maindisplay surface. Furthermore, the curved portion 40 can be referred toas a second display portion functioning as a sub display surface.

Here, the area of the second display portion is preferably smaller thanthat of the first display portion. In other words, the area of a surfacepositioned in the curved portion 40 and functioning as a sub displaysurface (second surface) of the light guide plate 59 d is preferablysmaller than that of a surface functioning as a main display surface(first surface) of the light guide plate 59 d.

In the curved portion 40, the light-emitting elements 57 providedbetween the light guide plate 59 d and the substrate 51 can display animage along the curved surface. Furthermore, the light-receiving element53 provided in the curved portion 40 can receive the infrared light IR,visible light, or the like reflected by a sensing target touching thecurved portion 40.

Here, it can also be said that the light guide plate 59 d includes thefirst portion, which is positioned in the first display portion and hasthe first surface, and the second portion, which has the second surfacethat connects with the first surface and has a different normaldirection from the first surface. The second portion is positioned inthe second display portion. It can also be said that the substrate 51includes a third portion provided along the first portion of the lightguide plate 59 d and a fourth portion provided along the second portionof the light guide plate 59 d.

A surface of the light guide plate 59 d, which is positioned in thefirst display portion, is preferably a flat surface. The surface mayinclude a curved surface portion having a smaller curvature than thecurved portion 40.

FIG. 5A illustrates an example in which the substrate 51 is supported bya support member 56. As the support member 56, part of a housing of anelectronic device into which the display device 50 h is incorporated canbe used. The side opposite to the side provided with the light guideplate 59 d of the substrate 51 is supported by the support member 56,which can increase the mechanical strength. It is favorable to supportthe substrate 51 with the support member 56 especially when a flexiblesubstrate is used as the substrate 51.

The light-emitting element 54 is provided for the end portion on thecurved portion 40 side of the light guide plate 59 d. Thus, thelight-emitting element 54 can be provided on the rear side of thesupport member 56. This enables a smaller bezel that surrounds a displayportion in an electronic device using the display device 50 h and canenhance the design of the electronic device.

Although an example in which the light guide plate 59 d, the substrate51, and the like are curved 180 degrees at the curved portion 40 isillustrated in FIG. 5A, there is no limitation thereto. For example,structures in which they are curved at an angle of greater than or equalto 30 degrees and less than or equal to 180 degrees, preferably greaterthan or equal to 60 degrees and less than or equal to 180 degrees,further preferably greater than or equal to 90 degrees and less than orequal to 180 degrees can be used.

A display device 50 i illustrated in FIG. 5B is an example in which thelight-emitting element 54 is provided on the side opposite to the curvedportion 40 side. The reflective layer 58 is provided for the end portionon the curved portion 40 side of the light guide plate 59 d.

A display device 50 j illustrated in FIG. 5C includes a pair of curvedportions 40 a and 40 b. A light guide plate 59 e includes a pair ofcurved portions each positioned in the second display portion, betweenwhich a portion positioned in the first display portion is sandwiched.

With this structure, both end portions of the light guide plate 59 e canbe folded back toward the side opposite to the main display surfaceside, whereby the bezel in an electronic device using the display device50 j can be substantially eliminated. Thus, an electronic device withexcellent design and convenience can be achieved.

A display device 50 k illustrated in FIG. 6A is an example in which acurved portion 40 c functioning as the second display portion has a flatsurface. A light guide plate 59 f includes a portion positioned in thefirst display portion and a portion positioned in the curved portion 40c functioning as the second display portion. A flat portion of the lightguide plate 59 f positioned in the curved portion 40 c is provided so asto be sandwiched between a pair of curved portions. In other words, inthe light guide plate 59 f, a curved portion is provided between theportion positioned in the first display portion and the flat portionpositioned in the curved portion 40 c.

It can also be said that the display device 50 k illustrated in FIG. 6Aincludes the first display portion functioning as the main displaysurface and the second display portion that is tilted away from thefirst display portion.

With this structure in which part of the curved portion 40 c has theflat portion, the contact area of the curved portion 40 c and a fingerthat touches the curved portion 40 c can be increased, enablingauthentication with higher accuracy.

Here, an angle (angle θ₁) formed between a surface positioned in thefirst display portion of the light guide plate 59 f and a surface of theflat portion positioned in the curved portion 40 c of the light guideplate 59 f is preferably greater than 0 degrees and less than or equalto 90 degrees. Specifically, the angle can be greater than or equal to15 degrees and less than or equal to 90 degrees, preferably greater thanor equal to 20 degrees and less than 90 degrees, further preferablygreater than or equal to 25 degrees and less than or equal to 90degrees. The angle θ₁ can be typically 30 degrees, 45 degrees, 60degrees, 75 degrees, or the like.

Furthermore, an angle (angle θ₂) formed between the surface of the flatportion positioned in the curved portion 40 c of the light guide plate59 f and a surface of a flat portion in the vicinity of thelight-emitting element 54 is preferably an angle obtained by subtractingthe above-described angle θ₁ from 180 degrees.

Here, the area of the second display portion is preferably smaller thanthat of the first display portion. In other words, the area of a surfacepositioned in the curved portion 40 c and functioning as a sub displaysurface (second surface) of the light guide plate 59 f is preferablysmaller than that of a surface functioning as a main display surface(first surface) of the light guide plate 59 f.

An example in which the light-emitting element 54 is provided on thecurved portion 40 c side of the light guide plate 59 f is illustrated inFIG. 6A; as in a display device 50 m illustrated in FIG. 6B, thelight-emitting element 54 may be provided on the side opposite to thecurved portion 40 c side of the light guide plate 59 f. In this case,the reflective layer 58 can be provided on the curved portion 40 c sideof the light guide plate 59 f.

A display device 50 n illustrated in FIG. 6C includes a pair of curvedportions 40 c and 40 d.

With this structure, both end portions of a light guide plate 59 gincluded in the display device 50 n can be folded back toward the sideopposite to the main display surface side, whereby the bezel in anelectronic device using the display device 50 n can be substantiallyeliminated. Thus, an electronic device with excellent design andconvenience can be achieved.

The above is the description of the structure examples of the lightguide plate.

Structure Example 3 of Display Device

More specific examples of the display device of one embodiment of thepresent invention will be described below.

Structure Example 3-1

FIG. 7A illustrates a schematic cross-sectional view of a display device10A.

The display device 10A includes a light-receiving element 110 and alight-emitting element 190. The light-receiving element 110 includes apixel electrode 111, a common layer 112, an active layer 113, a commonlayer 114, and a common electrode 115. The light-emitting element 190includes a pixel electrode 191, the common layer 112, a light-emittinglayer 193, the common layer 114, and the common electrode 115.

The pixel electrode 111, the pixel electrode 191, the common layer 112,the active layer 113, the light-emitting layer 193, the common layer114, and the common electrode 115 may each have a single-layer structureor a stacked-layer structure.

The pixel electrode 111 and the pixel electrode 191 are positioned overan insulating layer 214. The pixel electrode 111 and the pixel electrode191 can be formed using the same material in the same step.

The common layer 112 is positioned over the pixel electrode 111 and thepixel electrode 191. The common layer 112 is a layer shared by thelight-receiving element 110 and the light-emitting element 190.

The active layer 113 overlaps with the pixel electrode 111 with thecommon layer 112 therebetween. The light-emitting layer 193 overlapswith the pixel electrode 191 with the common layer 112 therebetween. Theactive layer 113 includes a first organic compound, and thelight-emitting layer 193 includes a second organic compound that isdifferent from the first organic compound.

The common layer 114 is positioned over the common layer 112, the activelayer 113, and the light-emitting layer 193. The common layer 114 is alayer shared by the light-receiving element 110 and the light-emittingelement 190.

The common electrode 115 includes a portion overlapping with the pixelelectrode 111 with the common layer 112, the active layer 113, and thecommon layer 114 therebetween. The common electrode 115 further includesa portion overlapping with the pixel electrode 191 with the common layer112, the light-emitting layer 193, and the common layer 114therebetween. The common electrode 115 is a layer shared by thelight-receiving element 110 and the light-emitting element 190.

In the display device of this embodiment, an organic compound is usedfor the active layer 113 of the light-receiving element 110. In thelight-receiving element 110, the layers other than the active layer 113can have structures in common with the layers in the light-emittingelement 190 (EL element). Therefore, the light-receiving element 110 canbe formed concurrently with the formation of the light-emitting element190 only by adding a step of depositing the active layer 113 in themanufacturing process of the light-emitting element 190. Thelight-emitting element 190 and the light-receiving element 110 can beformed over one substrate. Accordingly, the light-receiving element 110can be incorporated into the display device without a significantincrease in the number of manufacturing steps.

The display device 10A illustrates an example in which thelight-receiving element 110 and the light-emitting element 190 have acommon structure except that the active layer 113 of the light-receivingelement 110 and the light-emitting layer 193 of the light-emittingelement 190 are separately formed. Note that the structures of thelight-receiving element 110 and the light-emitting element 190 are notlimited thereto. The light-receiving element 110 and the light-emittingelement 190 may include separately formed layers other than the activelayer 113 and the light-emitting layer 193 (see display devices 10D,10E, and 10F described later). The light-receiving element 110 and thelight-emitting element 190 preferably include at least one layer used incommon (common layer). Thus, the light-receiving element 110 can beincorporated into the display device without a significant increase inthe number of manufacturing steps.

The display device 10A includes the light-receiving element 110, thelight-emitting element 190, a transistor 41, a transistor 42, and thelike between a pair of substrates (a substrate 151 and a substrate 152).

The display device 10A also includes a light guide plate 121 on theoutside of the substrate 152. A light-emitting element 122 that emitsinfrared light is provided at an end portion of the light guide plate121.

In the light-receiving element 110, the common layer 112, the activelayer 113, and the common layer 114, which are positioned between thepixel electrode 111 and the common electrode 115, can each also bereferred to as an organic layer (a layer including an organic compound).The pixel electrode 111 preferably has a function of reflecting visiblelight and infrared light. An end portion of the pixel electrode 111 iscovered with a bank 216. The common electrode 115 has a function oftransmitting visible light and infrared light.

The light-receiving element 110 has a function of sensing light.Specifically, the light-receiving element 110 is a photoelectricconversion element that receives light 22 entering through the lightguide plate 121 and converts the light 22 into an electric signal.

A light-blocking layer BM is provided on a surface of the substrate 152that faces the substrate 151. The light-blocking layer BM has an openingin a position overlapping with the light-receiving element 110 and in aposition overlapping with the light-emitting element 190. Providing thelight-blocking layer BM can control the range where the light-receivingelement 110 senses light.

For the light-blocking layer BM, a material that blocks light emittedfrom the light-emitting element can be used. The light-blocking layer BMpreferably absorbs visible light. As the light-blocking layer BM, ablack matrix can be formed using a metal material or a resin materialcontaining pigment (e.g., carbon black) or dye, for example. Thelight-blocking layer BM may have a stacked-layer structure of a redcolor filter, a green color filter, and a blue color filter.

Here, the light-receiving element 110 senses light that is scattered bya surface of the light guide plate 121. However, in some cases, lightemitted from the light-emitting element 190 is reflected inside thedisplay device 10A and enters the light-receiving element 110 withoutvia the light guide plate 121 or the like. The light-blocking layer BMcan reduce the influence of such stray light. For example, in the casewhere the light-blocking layer BM is not provided, light 23 a emittedfrom the light-emitting element 190 is reflected by the substrate 152and reflected light 23 b enters the light-receiving element 110 in somecases. Providing the light-blocking layer BM can inhibit the reflectedlight 23 b from entering the light-receiving element 110. Consequently,noise can be reduced, and the sensitivity of a sensor using thelight-receiving element 110 can be increased.

In the light-emitting element 190, the common layer 112, thelight-emitting layer 193, and the common layer 114, which are positionedbetween the pixel electrode 191 and the common electrode 115, can eachalso be referred to as an EL layer. The pixel electrode 191 preferablyhas a function of reflecting visible light and infrared light. An endportion of the pixel electrode 191 is covered with the bank 216. Thepixel electrode 111 and the pixel electrode 191 are electricallyinsulated from each other by the bank 216. As described above, thecommon electrode 115 has a function of transmitting visible light andinfrared light.

The light-emitting element 190 has a function of emitting visible light.Specifically, the light-emitting element 190 is an electroluminescentelement that emits light 21 to the substrate 152 side when voltage isapplied between the pixel electrode 191 and the common electrode 115.

It is preferable that the light-emitting layer 193 be formed not tooverlap with a light-receiving region of the light-receiving element110. This inhibits the light-emitting layer 193 from absorbing the light22, increasing the amount of light with which the light-receivingelement 110 is irradiated.

The pixel electrode 111 is electrically connected to a source or a drainof the transistor 41 through an opening provided in the insulating layer214. The end portion of the pixel electrode 111 is covered with the bank216.

The pixel electrode 191 is electrically connected to a source or a drainof the transistor 42 through an opening provided in the insulating layer214. The end portion of the pixel electrode 191 is covered with the bank216. The transistor 42 has a function of controlling the driving of thelight-emitting element 190.

The transistor 41 and the transistor 42 are in contact with a topsurface of the same layer (the substrate 151 in FIG. 7A).

At least part of a circuit electrically connected to the light-receivingelement 110 and a circuit electrically connected to the light-emittingelement 190 are preferably formed using the same material in the samestep. In that case, the thickness of the display device can be reducedcompared with the case where the two circuits are separately formed,resulting in simplification of the manufacturing steps.

The light-receiving element 110 and the light-emitting element 190 arepreferably covered with a protective layer 195. In FIG. 7A, theprotective layer 195 is provided on and in contact with the commonelectrode 115. Providing the protective layer 195 can inhibit entry ofimpurities such as water into the light-receiving element 110 and thelight-emitting element 190, so that the reliability of thelight-receiving element 110 and the light-emitting element 190 can beincreased. The protective layer 195 and the substrate 152 are bonded toeach other with an adhesive layer 142.

Note that as illustrated in FIG. 8A, the protective layer over thelight-receiving element 110 and the light-emitting element 190 may beomitted. In FIG. 8A, the common electrode 115 and the substrate 152 arebonded to each other with the adhesive layer 142.

A structure that does not include the light-blocking layer BM asillustrated in FIG. 8B may be employed. This can increase thelight-receiving area of the light-receiving element 110, furtherincreasing the sensitivity of the sensor.

Structure Example 3-2

FIG. 7B illustrates a cross-sectional view of a display device 10B. Notethat in the description of the display device below, components similarto those of the above-mentioned display device are not described in somecases.

The display device 10B illustrated in FIG. 7B includes a lens 149 inaddition to the components of the display device 10A.

The lens 149 is provided in a position overlapping with thelight-receiving element 110. In the display device 10B, the lens 149 isprovided in contact with the substrate 152. The lens 149 included in thedisplay device 10B is a convex lens having a convex surface on thesubstrate 151 side. Note that a convex lens having a convex surface onthe substrate 152 side may be provided in a position overlapping withthe light-receiving element 110.

In the case where the light-blocking layer BM and the lens 149 areformed on the same plane of the substrate 152, their formation order isnot limited. FIG. 7B illustrates an example in which the lens 149 isformed first; alternatively, the light-blocking layer BM may be formedfirst. In FIG. 7B, an end portion of the lens 149 is covered with thelight-blocking layer BM.

The display device 10B has a structure in which the light 22 enters thelight-receiving element 110 through the lens 149. With the lens 149, theimage-capturing range of the light-receiving element 110 can be narrowedas compared to the case where the lens 149 is not provided, therebyinhibiting overlap of the imaging ranges between the adjacentlight-receiving elements 110. Thus, a clear image with little blurringcan be captured. Given that the imaging range of the light-receivingelement 110 does not change, the lens 149 allows the size of a pinhole(corresponding to the size of an opening in BM that overlaps with thelight-receiving element 110 in FIG. 7B) to be increased, compared to thecase where the lens 149 is not provided. Hence, providing the lens 149can increase the amount of light entering the light-receiving element110.

As a method for forming the lens used in the display device of thisembodiment, a lens such as a microlens may be formed directly over thesubstrate or the light-receiving element, or a lens array formedseparately, such as a microlens array, may be bonded to the substrate.

Structure Example 3-3

FIG. 7C illustrates a schematic cross-sectional view of a display device10C. The display device 10C is different from the display device 10A inthat the substrate 151, the substrate 152, and the bank 216 are notincluded but a substrate 153, a substrate 154, an adhesive layer 155, aninsulating layer 212, and a bank 217 are included.

The substrate 153 and the insulating layer 212 are bonded to each otherwith the adhesive layer 155. The substrate 154 and the protective layer195 are bonded to each other with the adhesive layer 142.

The display device 10C has a structure obtained in such a manner thatthe insulating layer 212, the transistor 41, the transistor 42, thelight-receiving element 110, the light-emitting element 190, and thelike are formed over a formation substrate and then transferred onto thesubstrate 153. The substrate 153 and the substrate 154 preferably haveflexibility. Accordingly, the flexibility of the display device 10C canbe increased. For example, a resin is preferably used for each of thesubstrate 153 and the substrate 154.

For each of the substrate 153 and the substrate 154, a polyester resinsuch as polyethylene terephthalate (PET) or polyethylene naphthalate(PEN), a polyacrylonitrile resin, an acrylic resin, a polyimide resin, apolymethyl methacrylate resin, a polycarbonate (PC) resin, a polyethersulfone (PES) resin, a polyamide resin (e.g., nylon or aramid), apolysiloxane resin, a cycloolefin resin, a polystyrene resin, apolyamide-imide resin, a polyurethane resin, a polyvinyl chloride resin,a polyvinylidene chloride resin, a polypropylene resin, apolytetrafluoroethylene (PTFE) resin, an ABS resin, or cellulosenanofiber can be used, for example. Glass that is thin enough to haveflexibility may be used for one or both of the substrate 153 and thesubstrate 154.

As the substrate included in the display device of this embodiment, afilm having high optical isotropy may be used. Examples of the filmhaving high optical isotropy include a triacetyl cellulose (TAC, alsoreferred to as cellulose triacetate) film, a cycloolefin polymer (COP)film, a cycloolefin copolymer (COC) film, and an acrylic film.

The bank 217 preferably absorbs light emitted by the light-emittingelement. As the bank 217, a black matrix can be formed using a resinmaterial containing a pigment or dye, for example. Moreover, the bank217 can be formed of a colored insulating layer by using a brown resistmaterial.

In the case where a material that transmits light emitted by thelight-emitting element 190 is used for the bank 217, light 23 c emittedby the light-emitting element 190 might be reflected by the substrate154 and the bank 217 and reflected light 23 d might enter thelight-receiving element 110. In other cases, the light 23 c passesthrough the bank 217 and is reflected by a transistor, a wiring, or thelike, and thus reflected light enters the light-receiving element 110.When the bank 217 absorbs the light 23 c, the reflected light 23 d canbe inhibited from entering the light-receiving element 110.Consequently, noise can be reduced, and the sensitivity of a sensorusing the light-receiving element 110 can be increased.

The bank 217 preferably absorbs at least light having a wavelength thatis sensed by the light-receiving element 110. For example, in the casewhere the light-receiving element 110 senses red light emitted by thelight-emitting element 190, the bank 217 preferably absorbs at least redlight. For example, when the bank 217 includes a blue color filter, thebank 217 can absorb the red light 23 c and thus the reflected light 23 dcan be inhibited from entering the light-receiving element 110.

Structure Example 3-4

Although the light-emitting element and the light-receiving elementinclude two common layers in the above examples, one embodiment of thepresent invention is not limited thereto. Examples in which commonlayers have different structures are described below.

FIG. 9A illustrates a schematic cross-sectional view of a display device10D. The display device 10D is different from the display device 10A inthat the common layer 114 is not included and a buffer layer 184 and abuffer layer 194 are included. The buffer layer 184 and the buffer layer194 may each have a single-layer structure or a stacked-layer structure.

In the display device 10D, the light-receiving element 110 includes thepixel electrode 111, the common layer 112, the active layer 113, thebuffer layer 184, and the common electrode 115. In the display device10D, the light-emitting element 190 includes the pixel electrode 191,the common layer 112, the light-emitting layer 193, the buffer layer194, and the common electrode 115.

The display device 10D shows an example in which the buffer layer 184between the common electrode 115 and the active layer 113 and the bufferlayer 194 between the common electrode 115 and the light-emitting layer193 are formed separately. As the buffer layer 184 and the buffer layer194, one or both of an electron-injection layer and anelectron-transport layer can be formed, for example.

FIG. 9B illustrates a schematic cross-sectional view of a display device10E. The display device 10E is different from the display device 10A inthat the common layer 112 is not included and a buffer layer 182 and abuffer layer 192 are included. The buffer layer 182 and the buffer layer192 may each have a single-layer structure or a stacked-layer structure.

In the display device 10E, the light-receiving element 110 includes thepixel electrode 111, the buffer layer 182, the active layer 113, thecommon layer 114, and the common electrode 115. In the display device10E, the light-emitting element 190 includes the pixel electrode 191,the buffer layer 192, the light-emitting layer 193, the common layer114, and the common electrode 115.

The display device 10E shows an example in which the buffer layer 182between the pixel electrode 111 and the active layer 113 and the bufferlayer 192 between the pixel electrode 191 and the light-emitting layer193 are formed separately. As the buffer layer 182 and the buffer layer192, one or both of a hole-injection layer and a hole-transport layercan be formed, for example.

FIG. 9C illustrates a schematic cross-sectional view of a display device10F. The display device 10F is different from the display device 10A inthat the common layer 112 and the common layer 114 are not included andthe buffer layer 182, the buffer layer 184, the buffer layer 192, andthe buffer layer 194 are included.

In the display device 10F, the light-receiving element 110 includes thepixel electrode 111, the buffer layer 182, the active layer 113, thebuffer layer 184, and the common electrode 115. In the display device10F, the light-emitting element 190 includes the pixel electrode 191,the buffer layer 192, the light-emitting layer 193, the buffer layer194, and the common electrode 115.

In the formation of the light-receiving element 110 and thelight-emitting element 190, not only the active layer 113 and thelight-emitting layer 193 but also other layers can be formed separately.

The display device 10F shows an example in which the light-receivingelement 110 and the light-emitting element 190 do not have a commonlayer between the pair of electrodes (the pixel electrode 111 or thepixel electrode 191 and the common electrode 115). The light-receivingelement 110 and the light-emitting element 190 included in the displaydevice 10F can be formed in the following manner: the pixel electrode111 and the pixel electrode 191 are formed over the insulating layer 214using the same material in the same step; the buffer layer 182, theactive layer 113, and the buffer layer 184 are formed over the pixelelectrode 111, and the buffer layer 192, the light-emitting layer 193,and the buffer layer 194 are formed over the pixel electrode 191; andthen, the common electrode 115 is formed to cover the buffer layer 184,the buffer layer 194, and the like.

Note that the formation order of the stacked-layer structure of thebuffer layer 182, the active layer 113, and the buffer layer 184 and thestacked-layer structure of the buffer layer 192, the light-emittinglayer 193, and the buffer layer 194 is not particularly limited. Forexample, after the buffer layer 182, the active layer 113, and thebuffer layer 184 are deposited, the buffer layer 192, the light-emittinglayer 193, and the buffer layer 194 may be formed. In contrast, thebuffer layer 192, the light-emitting layer 193, and the buffer layer 194may be formed before the buffer layer 182, the active layer 113, and thebuffer layer 184 are deposited. Alternate deposition of the buffer layer182, the buffer layer 192, the active layer 113, the light-emittinglayer 193, and the like in this order is also possible.

Structure Example 4 of Display Device

More specific structure examples of the display device of one embodimentof the present invention will be described below.

Structure Example 4-1

FIG. 10 illustrates a perspective view of a display device 100A.

The display device 100A has a structure in which the substrate 151 andthe substrate 152 are bonded to each other. The light guide plate 121 isprovided over the substrate 152. In FIG. 10, the substrate 152 and thelight guide plate 121 are denoted by a dashed line.

The display device 100A includes a display portion 162, a circuit 164, awiring 165, and the like. FIG. 10 illustrates an example in which thedisplay device 100A is provided with an IC (integrated circuit) 173 andan FPC 172. Thus, the structure illustrated in FIG. 10 can be regardedas a display module including the display device 100A, the IC 173, andthe FPC 172.

As the circuit 164, a scan line driver circuit can be used.

The wiring 165 has a function of supplying a signal and power to thedisplay portion 162 and the circuit 164. The signal and power are inputto the wiring 165 from the outside through the FPC 172 or from the IC173.

FIG. 10 illustrates an example in which the IC 173 is provided over thesubstrate 151 by a COG (Chip On Glass) method, a COF (Chip On Film)method, or the like. An IC including a scan line driver circuit, asignal line driver circuit, or the like can be used as the IC 173, forexample. Note that the display device 100A and the display module mayhave a structure that does not include an IC. The IC may be mounted onthe FPC 172 by a COF method or the like.

FIG. 11 illustrates an example of a cross section of part of a regionincluding the FPC 172, part of a region including the circuit 164, partof a region including the display portion 162, and part of a regionincluding an end portion of the display device 100A illustrated in FIG.10.

The display device 100A illustrated in FIG. 11 includes a transistor201, a transistor 205, a transistor 206, the light-emitting element 190,the light-receiving element 110, and the like between the substrate 151and the substrate 152. The light guide plate 121 is provided over thesubstrate 152. The light-emitting element 122 is provided at an endportion of the light guide plate 121.

The substrate 152 and the insulating layer 214 are attached to eachother with the adhesive layer 142. A solid sealing structure, a hollowsealing structure, or the like can be employed to seal thelight-emitting element 190 and the light-receiving element 110. In FIG.11, a space 143 surrounded by the substrate 152, the adhesive layer 142,and the insulating layer 214 is filled with an inert gas (e.g., nitrogenor argon), that is, a hollow sealing structure is employed. The adhesivelayer 142 may be provided to overlap with the light-emitting element190. The space 143 surrounded by the substrate 152, the adhesive layer142, and the insulating layer 214 may be filled with a resin differentfrom that of the adhesive layer 142.

The light-emitting element 190 has a stacked-layer structure in whichthe pixel electrode 191, the common layer 112, the light-emitting layer193, the common layer 114, and the common electrode 115 are stacked inthis order from the insulating layer 214 side. The pixel electrode 191is connected to a conductive layer 222 b included in the transistor 206through an opening provided in the insulating layer 214. The transistor206 has a function of controlling the driving of the light-emittingelement 190. An end portion of the pixel electrode 191 is covered withthe bank 216. The pixel electrode 191 includes a material that reflectsvisible light and infrared light, and the common electrode 115 includesa material that transmits visible light and infrared light.

The light-receiving element 110 has a stacked-layer structure in whichthe pixel electrode 111, the common layer 112, the active layer 113, thecommon layer 114, and the common electrode 115 are stacked in this orderfrom the insulating layer 214 side. The pixel electrode 111 iselectrically connected to the conductive layer 222 b included in thetransistor 205 through an opening provided in the insulating layer 214.An end portion of the pixel electrode 111 is covered with the bank 216.The pixel electrode 111 includes a material that reflects visible lightand infrared light, and the common electrode 115 includes a materialthat transmits visible light and infrared light.

Light emitted from the light-emitting element 190 is emitted toward thesubstrate 152 side. Light enters the light-receiving element 110 throughthe substrate 152 and the space 143. For the substrate 152, a materialthat has high transmittance with respect to visible light and infraredlight is preferably used.

The pixel electrode 111 and the pixel electrode 191 can be formed usingthe same material in the same step. The common layer 112, the commonlayer 114, and the common electrode 115 are used in both thelight-receiving element 110 and the light-emitting element 190. Thelight-receiving element 110 and the light-emitting element 190 can havecommon components except the active layer 113 and the light-emittinglayer 193. Thus, the light-receiving element 110 can be incorporatedinto the display device 100A without a significant increase in thenumber of manufacturing steps.

The light-blocking layer BM is provided on the surface of the substrate152 that faces the substrate 151. The light-blocking layer BM has anopening in a position overlapping with the light-receiving element 110and in a position overlapping with the light-emitting element 190.Providing the light-blocking layer BM can control the range where thelight-receiving element 110 senses light. Furthermore, with thelight-blocking layer BM, light from the light-emitting element 190 canbe inhibited from directly entering the light-receiving element 110.Hence, a sensor with less noise and high sensitivity can be obtained.

The transistor 201, the transistor 205, and the transistor 206 areformed over the substrate 151. These transistors can be formed using thesame materials in the same steps.

An insulating layer 211, an insulating layer 213, an insulating layer215, and the insulating layer 214 are provided in this order over thesubstrate 151. Parts of the insulating layer 211 function as gateinsulating layers of the transistors. Parts of the insulating layer 213function as gate insulating layers of the transistors. The insulatinglayer 215 is provided to cover the transistors. The insulating layer 214is provided to cover the transistors and has a function of aplanarization layer. Note that there is no limitation on the number ofgate insulating layers and the number of insulating layers covering thetransistors, and each insulating layer may have either a single layer ortwo or more layers.

A material into which impurities such as water and hydrogen do noteasily diffuse is preferably used for at least one of the insulatinglayers that cover the transistors. This allows the insulating layer toserve as a barrier layer. Such a structure can effectively inhibitdiffusion of impurities into the transistors from the outside andincrease the reliability of the display device.

An inorganic insulating film is preferably used as each of theinsulating layer 211, the insulating layer 213, and the insulating layer215. As the inorganic insulating film, for example, a silicon nitridefilm, a silicon oxynitride film, a silicon oxide film, a silicon nitrideoxide film, an aluminum oxide film, an aluminum nitride film, or thelike can be used. A hafnium oxide film, an yttrium oxide film, azirconium oxide film, a gallium oxide film, a tantalum oxide film, amagnesium oxide film, a lanthanum oxide film, a cerium oxide film, aneodymium oxide film, or the like may also be used. A stack includingtwo or more of the above insulating films may also be used.

Here, an organic insulating film often has a lower barrier property thanan inorganic insulating film. Therefore, the organic insulating filmpreferably has an opening in the vicinity of an end portion of thedisplay device 100A. This can inhibit diffusion of impurities from theend portion of the display device 100A through the organic insulatingfilm. Alternatively, in order to prevent the organic insulating filmfrom being exposed at the end portion of the display device 100A, theorganic insulating film may be formed so that its end portion ispositioned on the inner side than the end portion of the display device100A.

An organic insulating film is suitable for the insulating layer 214functioning as a planarization layer. Examples of materials that can beused for the organic insulating film include an acrylic resin, apolyimide resin, an epoxy resin, a polyamide resin, a polyimide-amideresin, a siloxane resin, a benzocyclobutene-based resin, a phenol resin,and precursors of these resins.

In a region 228 illustrated in FIG. 11, an opening is formed in theinsulating layer 214. This can inhibit diffusion of impurities into thedisplay portion 162 from the outside through the insulating layer 214even when an organic insulating film is used as the insulating layer214. Thus, the reliability of the display device 100A can be increased.

Each of the transistor 201, the transistor 205, and the transistor 206includes a conductive layer 221 functioning as a gate, the insulatinglayer 211 functioning as the gate insulating layer, a conductive layer222 a and the conductive layer 222 b functioning as a source and adrain, a semiconductor layer 231, the insulating layer 213 functioningas the gate insulating layer, and a conductive layer 223 functioning asa gate. Here, a plurality of layers obtained by processing the sameconductive film are shown with the same hatching pattern. The insulatinglayer 211 is positioned between the conductive layer 221 and thesemiconductor layer 231. The insulating layer 213 is positioned betweenthe conductive layer 223 and the semiconductor layer 231.

There is no particular limitation on the structure of the transistorsincluded in the display device of this embodiment. For example, a planartransistor, a staggered transistor, or an inverted staggered transistorcan be used. A top-gate or a bottom-gate transistor structure may beemployed. Alternatively, gates may be provided above and below asemiconductor layer in which a channel is formed.

The structure in which the semiconductor layer where a channel is formedis provided between two gates is used for the transistor 201, thetransistor 205, and the transistor 206. The two gates may be connectedto each other and supplied with the same signal to drive the transistor.Alternatively, a potential for controlling the threshold voltage may besupplied to one of the two gates and a potential for driving may besupplied to the other to control the threshold voltage of thetransistor.

There is no particular limitation on the crystallinity of asemiconductor material used for the transistors, and any of an amorphoussemiconductor, a single crystal semiconductor, and a semiconductorhaving crystallinity other than single crystal (a microcrystallinesemiconductor, a polycrystalline semiconductor, or a semiconductorpartly including crystal regions) may be used. A single crystalsemiconductor or a semiconductor having crystallinity is preferablyused, in which case deterioration of the transistor characteristics canbe suppressed.

A semiconductor layer of a transistor preferably includes a metal oxide(also referred to as an oxide semiconductor). Alternatively, thesemiconductor layer of the transistor may include silicon. Examples ofsilicon include amorphous silicon and crystalline silicon (e.g.,low-temperature polysilicon or single crystal silicon).

The semiconductor layer preferably includes indium, M (M is one or morekinds selected from gallium, aluminum, silicon, boron, yttrium, tin,copper, vanadium, beryllium, titanium, iron, nickel, germanium,zirconium, molybdenum, lanthanum, cerium, neodymium, hafnium, tantalum,tungsten, and magnesium), and zinc, for example. Specifically, M ispreferably one or more kinds selected from aluminum, gallium, yttrium,and tin.

It is particularly preferable to use an oxide containing indium (In),gallium (Ga), and zinc (Zn) (also referred to as IGZO) for thesemiconductor layer.

In the case where the semiconductor layer is an In-M-Zn oxide, theatomic ratio of In to M in a sputtering target used for depositing theIn-M-Zn oxide is preferably higher than or equal to 1. Examples of theatomic ratio of the metal elements in such a sputtering target includeIn:M:Zn=1:1:1, In:M:Zn=1:1:1.2, In:M:Zn=2:1:3, In:M:Zn=3:1:2,In:M:Zn=4:2:3, In:M:Zn=4:2:4.1, In:M:Zn=5:1:6, In:M:Zn=5:1:7,In:M:Zn=5:1:8, In:M:Zn=6:1:6, and In:M:Zn=5:2:5.

A target including a polycrystalline oxide is preferably used as thesputtering target, in which case the semiconductor layer havingcrystallinity is easily formed. Note that the atomic ratio in thedeposited semiconductor layer may vary from the above atomic ratiobetween metal elements in the sputtering target in a range of ±40%. Forexample, in the case where the composition of a sputtering target usedfor the semiconductor layer is In:Ga:Zn=4:2:4.1 [atomic ratio], thecomposition of the semiconductor layer to be deposited is sometimes inthe neighborhood of In:Ga:Zn=4:2:3 [atomic ratio].

Note that when the atomic ratio is described as In:Ga:Zn=4:2:3 or in theneighborhood thereof, the case is included where Ga is greater than orequal to 1 and less than or equal to 3 and Zn is greater than or equalto 2 and less than or equal to 4 with In being 4. When the atomic ratiois described as In:Ga:Zn=5:1:6 or in the neighborhood thereof, the caseis included where Ga is greater than 0.1 and less than or equal to 2 andZn is greater than or equal to 5 and less than or equal to 7 with Inbeing 5. When the atomic ratio is described as In:Ga:Zn=1:1:1 or in theneighborhood thereof, the case is included where Ga is greater than 0.1and less than or equal to 2 and Zn is greater than 0.1 and less than orequal to 2 with In being 1.

The transistor included in the circuit 164 and the transistor includedin the display portion 162 may have the same structure or differentstructures. A plurality of transistors included in the circuit 164 mayhave the same structure or two or more kinds of structures. Similarly, aplurality of transistors included in the display portion 162 may havethe same structure or two or more kinds of structures.

A connection portion 204 is provided in a region of the substrate 151that does not overlap with the substrate 152. In the connection portion204, the wiring 165 is electrically connected to the FPC 172 via aconductive layer 166 and a connection layer 242. On the top surface ofthe connection portion 204, the conductive layer 166 obtained byprocessing the same conductive film as the pixel electrode 191 isexposed. Thus, the connection portion 204 and the FPC 172 can beelectrically connected to each other through the connection layer 242.

Any of a variety of optical members can be provided between thesubstrate 152 and the light guide plate 121 or on the outside of thelight guide plate 121. Examples of the optical members include apolarizing plate, a retardation plate, a light diffusion layer (adiffusion film or the like), an anti-reflective layer, and alight-condensing film. Furthermore, an antistatic film inhibiting theattachment of dust, a water repellent film suppressing the attachment ofstain, a hard coat film inhibiting generation of a scratch caused by theuse, a shock absorbing layer, or the like may be provided on the outsideof the substrate 152. Note that when a member having high lightdiffusion properties is provided in contact with the light guide plate121, infrared light diffusing inside the light guide plate 121 isscattered at the interface therebetween; thus, a member having low lightdiffusion properties is preferably provided therebetween.

For each of the substrate 151 and the substrate 152, glass, quartz,ceramic, sapphire, resin, or the like can be used. When a flexiblematerial is used for the substrate 151 and the substrate 152, theflexibility of the display device can be increased.

As the adhesive layer 142, the adhesive layer 155, and the like, avariety of curable adhesives, e.g., a photocurable adhesive such as anultraviolet curable adhesive, a reactive curable adhesive, athermosetting adhesive, and an anaerobic adhesive can be used. Examplesof these adhesives include an epoxy resin, an acrylic resin, a siliconeresin, a phenol resin, a polyimide resin, an imide resin, a PVC(polyvinyl chloride) resin, a PVB (polyvinyl butyral) resin, and an EVA(ethylene vinyl acetate) resin. In particular, a material with lowmoisture permeability, such as an epoxy resin, is preferred.Alternatively, a two-component resin may be used. An adhesive sheet orthe like may be used.

As the connection layer 242, an anisotropic conductive film (ACF), ananisotropic conductive paste (ACP), or the like can be used.

The light-emitting element 190 may be of a top emission type, a bottomemission type, a dual emission type, or the like. A conductive film thattransmits visible light is used as the electrode through which light isextracted. A conductive film that reflects visible light is preferablyused as the electrode through which light is not extracted.

The light-emitting element 190 includes at least the light-emittinglayer 193. The light-emitting element 190 may further include, as alayer other than the light-emitting layer 193, a layer containing asubstance with a high hole-injection property, a substance with a highhole-transport property, a hole-blocking material, a substance with ahigh electron-transport property, a substance with a highelectron-injection property, a substance with a bipolar property (asubstance with a high electron- and hole-transport property), or thelike. For example, the common layer 112 preferably includes one or bothof a hole-injection layer and a hole-transport layer. For example, thecommon layer 114 preferably includes one or both of anelectron-transport layer and an electron-injection layer.

The common layer 112, the light-emitting layer 193, and the common layer114 may use either a low molecular compound or a high molecular compoundand may also contain an inorganic compound. The layers that constitutethe common layer 112, the light-emitting layer 193, and the common layer114 can each be formed by a method such as an evaporation method(including a vacuum evaporation method), a transfer method, a printingmethod, an inkjet method, or a coating method.

The light-emitting layer 193 may contain an inorganic compound such asquantum dots as a light-emitting material.

The active layer 113 of the light-receiving element 110 includes asemiconductor. Examples of the semiconductor include an inorganicsemiconductor such as silicon and an organic semiconductor including anorganic compound. This embodiment shows an example in which an organicsemiconductor is used as the semiconductor included in the active layer.The use of an organic semiconductor is preferable because thelight-emitting layer 193 of the light-emitting element 190 and theactive layer 113 of the light-receiving element 110 can be formed by thesame method (e.g., a vacuum evaporation method) and thus the samemanufacturing apparatus can be used.

Examples of an n-type semiconductor material included in the activelayer 113 are electron-accepting organic semiconductor materials such asfullerene (e.g., C₆₀ and C₇₀) and derivatives thereof. As a p-typesemiconductor material included in the active layer 113, anelectron-donating organic semiconductor material such as copper(II)phthalocyanine (CuPc), tetraphenyldibenzoperiflanthene (DBP), or zincphthalocyanine (ZnPc) can be given.

For example, the active layer 113 is preferably formed by co-evaporationof an n-type semiconductor and a p-type semiconductor.

As materials that can be used for a gate, a source, and a drain of atransistor and conductive layers such as a variety of wirings andelectrodes included in a display device, metals such as aluminum,titanium, chromium, nickel, copper, yttrium, zirconium, molybdenum,silver, tantalum, or tungsten, an alloy containing any of these metalsas its main component, and the like can be given. A film containing anyof these materials can be used in a single layer or as a stacked-layerstructure.

As a light-transmitting conductive material, a conductive oxide such asindium oxide, indium tin oxide, indium zinc oxide, zinc oxide, or zincoxide containing gallium, or graphene can be used. Alternatively, ametal material such as gold, silver, platinum, magnesium, nickel,tungsten, chromium, molybdenum, iron, cobalt, copper, palladium, ortitanium, or an alloy material containing the metal material can beused. Further alternatively, a nitride of the metal material (e.g.,titanium nitride) or the like may be used. Note that in the case ofusing the metal material or the alloy material (or the nitride thereof),the thickness is preferably set small enough to be able to transmitlight. A stacked-layer film of any of the above materials can be used asa conductive layer. For example, a stacked-layer film of indium tinoxide and an alloy of silver and magnesium, or the like is preferablyused for increased conductivity. These materials can also be used forconductive layers such as a variety of wirings and electrodes thatconstitute a display device, and conductive layers (conductive layersfunctioning as a pixel electrode or a common electrode) included in adisplay element.

As an insulating material that can be used for each insulating layer,for example, a resin such as an acrylic resin or an epoxy resin, and aninorganic insulating material such as silicon oxide, silicon oxynitride,silicon nitride oxide, silicon nitride, or aluminum oxide can be given.

Structure Example 4-2

FIG. 12A illustrates a cross-sectional view of a display device 100B.The display device 100B is different from the display device 100A mainlyin that the lens 149 and the protective layer 195 are included.

Providing the protective layer 195 covering the light-receiving element110 and the light-emitting element 190 can inhibit diffusion ofimpurities such as water into the light-receiving element 110 and thelight-emitting element 190, so that the reliability of thelight-receiving element 110 and the light-emitting element 190 can beincreased.

In the region 228 in the vicinity of an end portion of the displaydevice 100B, the insulating layer 215 and the protective layer 195 arepreferably in contact with each other through an opening in theinsulating layer 214. In particular, the inorganic insulating filmincluded in the insulating layer 215 and the inorganic insulating filmincluded in the protective layer 195 are preferably in contact with eachother. Thus, diffusion of impurities from the outside into the displayportion 162 through the organic insulating film can be inhibited. Thus,the reliability of the display device 100B can be increased.

FIG. 12B illustrates an example in which the protective layer 195 has athree-layer structure. In FIG. 12B, the protective layer 195 includes aninorganic insulating layer 195 a over the common electrode 115, anorganic insulating layer 195 b over the inorganic insulating layer 195a, and an inorganic insulating layer 195 c over the organic insulatinglayer 195 b.

An end portion of the inorganic insulating layer 195 a and an endportion of the inorganic insulating layer 195 c extend beyond an endportion of the organic insulating layer 195 b and are in contact witheach other. The inorganic insulating layer 195 a is in contact with theinsulating layer 215 (inorganic insulating layer) through the opening inthe insulating layer 214 (organic insulating layer). Accordingly, thelight-receiving element 110 and the light-emitting element 190 can besurrounded by the insulating layer 215 and the protective layer 195,whereby the reliability of the light-receiving element 110 and thelight-emitting element 190 can be increased.

As described above, the protective layer 195 may have a stacked-layerstructure of an organic insulating film and an inorganic insulatingfilm. In that case, an end portion of the inorganic insulating filmpreferably extends beyond an end portion of the organic insulating film.

The lens 149 is provided on the surface of the substrate 152 that facesthe substrate 151. The lens 149 has a convex surface on the substrate151 side. It is preferable that the light-receiving region of thelight-receiving element 110 overlap with the lens 149 and not overlapwith the light-emitting layer 193. Thus, the sensitivity and accuracy ofa sensor using the light-receiving element 110 can be increased.

The refractive index of the lens 149 with respect to infrared light ispreferably greater than or equal to 1.3 and less than or equal to 2.5.The lens 149 can be formed using at least one of an inorganic materialand an organic material. For example, a material containing a resin canbe used for the lens 149. Moreover, a material containing at least oneof an oxide and a sulfide can be used for the lens 149.

Specifically, a resin containing chlorine, bromine, or iodine, a resincontaining a heavy metal atom, a resin having an aromatic ring, a resincontaining sulfur, or the like can be used for the lens 149.Alternatively, a material containing a resin and nanoparticles of amaterial having a higher refractive index than the resin can be used forthe lens 149. Titanium oxide, zirconium oxide, or the like can be usedfor the nanoparticles.

In addition, cerium oxide, hafnium oxide, lanthanum oxide, magnesiumoxide, niobium oxide, tantalum oxide, titanium oxide, yttrium oxide,zinc oxide, an oxide containing indium and tin, an oxide containingindium, gallium, and zinc, and the like can be used for the lens 149.Alternatively, zinc sulfide or the like can be used for the lens 149.

In the display device 100B, the protective layer 195 and the substrate152 are bonded to each other with the adhesive layer 142. The adhesivelayer 142 is provided to overlap with the light-receiving element 110and the light-emitting element 190; that is, the display device 100Bemploys a solid sealing structure.

Structure Example 4-3

FIG. 13A illustrates a cross-sectional view of a display device 100C.The display device 100C is different from the display device 100B mainlyin the structure of the transistors and including neither thelight-blocking layer BM nor the lens 149.

The display device 100C includes a transistor 208, a transistor 209, anda transistor 210 over the substrate 151.

Each of the transistor 208, the transistor 209, and the transistor 210includes the conductive layer 221 functioning as a gate, the insulatinglayer 211 functioning as a gate insulating layer, a semiconductor layerincluding a channel formation region 231 i and a pair of low-resistanceregions 231 n, the conductive layer 222 a connected to one of the pairof low-resistance regions 231 n, the conductive layer 222 b connected tothe other of the pair of low-resistance regions 231 n, an insulatinglayer 225 functioning as a gate insulating layer, the conductive layer223 functioning as a gate, and the insulating layer 215 covering theconductive layer 223. The insulating layer 211 is positioned between theconductive layer 221 and the channel formation region 231 i. Theinsulating layer 225 is positioned between the conductive layer 223 andthe channel formation region 231 i.

The conductive layer 222 a and the conductive layer 222 b are connectedto the corresponding low-resistance regions 231 n through openingsprovided in the insulating layer 225 and the insulating layer 215. Oneof the conductive layer 222 a and the conductive layer 222 b serves as asource, and the other serves as a drain.

The pixel electrode 191 of the light-emitting element 190 iselectrically connected to one of the pair of low-resistance regions 231n of the transistor 208 through the conductive layer 222 b.

The pixel electrode 111 of the light-receiving element 110 iselectrically connected to the other of the pair of low-resistanceregions 231 n of the transistor 209 through the conductive layer 222 b.

FIG. 13A illustrates an example in which the insulating layer 225 coversa top surface and a side surface of the semiconductor layer. Meanwhile,FIG. 13B illustrates an example in which the insulating layer 225overlaps with the channel formation region 231 i of the semiconductorlayer 231 and does not overlap with the low-resistance regions 231 n.The structure shown in FIG. 13B can be manufactured by processing theinsulating layer 225 using the conductive layer 223 as a mask, forexample. In FIG. 13B, the insulating layer 215 is provided to cover theinsulating layer 225 and the conductive layer 223, and the conductivelayer 222 a and the conductive layer 222 b are connected to thelow-resistance regions 231 n through the openings in the insulatinglayer 215. Furthermore, an insulating layer 218 covering the transistormay be provided.

Structure Example 4-4

FIG. 14 illustrates a cross-sectional view of a display device 100D. Thedisplay device 100D is different from the display device 100C mainly inthe structure of the substrates.

The display device 100D does not include the substrate 151 and thesubstrate 152 and includes the substrate 153, the substrate 154, theadhesive layer 155, and the insulating layer 212.

The substrate 153 and the insulating layer 212 are bonded to each otherwith the adhesive layer 155. The substrate 154 and the protective layer195 are bonded to each other with the adhesive layer 142.

The display device 100D has a structure obtained in such a manner thatthe insulating layer 212, the transistor 208, the transistor 209, thelight-receiving element 110, the light-emitting element 190, and thelike are formed over a formation substrate and then transferred onto thesubstrate 153. The substrate 153 and the substrate 154 preferably haveflexibility. Accordingly, the flexibility of the display device 100D canbe increased.

The above-described inorganic insulating film that can be used as theinsulating layer 211, the insulating layer 213, and the insulating layer215 can be used as the insulating layer 212. Alternatively, astacked-layer film of an organic insulating film and an inorganicinsulating film may be used as the insulating layer 212. In that case, afilm on the transistor 209 side is preferably an inorganic insulatingfilm.

The above is the description of the structure examples of the displaydevice.

The display device of this embodiment includes a light-receiving elementand a light-emitting element in a display portion, and the displayportion has both a function of displaying an image and a function ofsensing light. Thus, the size and weight of an electronic device can bereduced as compared to the case where a sensor is provided outside adisplay portion or outside a display device. Moreover, an electronicdevice having more functions can be achieved by a combination of thedisplay device of this embodiment and a sensor provided outside thedisplay portion or outside the display device.

In the light-receiving element, at least one of the layers other thanthe active layer can have a structure in common with a layer in thelight-emitting element (EL element). Also in the light-receivingelement, all of the layers other than the active layer can havestructures in common with the layers in the light-emitting element (ELelement). For example, the light-emitting element and thelight-receiving element can be formed over one substrate only by addinga step of depositing the active layer in the manufacturing process ofthe light-emitting element. In the light-receiving element and thelight-emitting element, their pixel electrodes can be formed using thesame material in the same step, and their common electrodes can beformed using the same material in the same step. When a circuitelectrically connected to the light-receiving element and a circuitelectrically connected to the light-emitting element are formed usingthe same materials in the same steps, the manufacturing process of thedisplay device can be simplified. In such a manner, a display devicethat incorporates a light-receiving element and is highly convenient canbe manufactured without complicated steps.

Structure Example of Electronic Device

The display device of one embodiment of the present invention can obtaina variety of biological data with the use of infrared light and visiblelight. Such biological data can be used for both user's personalauthentication uses and health care uses.

Typical examples of biological data that can be obtained using thedisplay device of one embodiment of the present invention and can beused for personal authentication include data on a fingerprint, a palmprint, a vein, and the like. Such biological data can be obtained usingvisible light or infrared light. It is particularly preferable that dataon a vein be obtained using infrared light.

Examples of biological data that can be obtained using the displaydevice of one embodiment of the present invention and can be used forhealth care uses include data on the pulse wave, the blood sugar level,oxygen saturation, the neutral fat concentration, and the like.

Furthermore, a unit for obtaining another biological data is preferablyprovided in an electronic device including the display device. Examplesof such biological data include internal biological data on anelectrocardiogram, blood pressure, the body temperature, and the likeand superficial biological data on facial expression, complexion, apupil, and the like. In addition, data on the number of steps taken,exercise intensity, a height difference in a movement, and a meal (e.g.,calorie intake and nutrients) are important for health care. The use ofa plurality of kinds of biological data and the like enables complexmanagement of physical conditions, leading to not only daily healthmanagement but also early detection of injuries and diseases.

Blood pressure can be calculated from an electrocardiogram and adifference in timing of two pulsations of a pulse wave (a period ofpulse wave propagation time), for example. High blood pressure resultsin a short pulse wave propagation time, whereas low blood pressureresults in a long pulse wave propagation time. The body conditions of auser can be estimated from a relationship between the heart rate andblood pressure that is calculated from an electrocardiogram and a pulsewave. For example, when both the heart rate and blood pressure are high,the user can be estimated to be nervous or excited, whereas when boththe heart rate and blood pressure are low, the user can be estimated tobe relaxed. When the state where blood pressure is low and the heartrate is high is continued, the user might suffer from a heart disease orthe like.

The user can check the biological data measured with the electronicdevice, one's own body conditions estimated on the basis of the data,and the like at any time; thus, health awareness is improved. This mayinspire the user to reconsider the daily habits, for example, to avoidover-eating and over-drinking, get enough exercise, and manage one'sphysical conditions, and to have a medical examination at a medicalinstitution as necessary.

Structure Example 1

FIG. 15A illustrates a schematic view of an electronic device 80. Theelectronic device 80 can be used as a smartphone. The electronic device80 includes at least a housing 82, a display portion 81 a, and a displayportion 81 b. The display portion 81 a functions as a main displaysurface, and the display portion 81 b functions as a sub display surfaceand has a curved surface shape along a side surface of the housing 82. Adisplay device of one embodiment of the present invention is used in thedisplay portion 81 a and the display portion 81 b.

As illustrated in FIG. 15A, the display portion 81 b is provided in aposition that is naturally touched by the finger 60 when the user graspsthe electronic device 80 with a hand 60 a. In this case, the electronicdevice 80 can obtain a fingerprint of the finger 60 touching the displayportion 81 b and execute fingerprint authentication. Accordingly, theuser can unconsciously execute an authentication operation at the sametime when the user performs an action of holding the electronic device80. Therefore, at the point when the user takes the electronic device 80in the hand and turns the eyes to the screen, the authentication hasalready been finished, the user has logged in the electronic device, andthe electronic device is ready to use. Thus, the electronic device canbe highly safe and convenient.

Furthermore, when the display portion 81 a is touched by the finger 60as illustrated in FIG. 15B, user's biological data can be obtained fromthe finger 60. For example, capturing of an image of the shape of a veinand capturing of an image of an arteriole can be executed. From the dataof the captured image, various biological data such as a pulse or anoxygen concentration can be obtained.

When the finger 60 touches the display portion 81 b as illustrated inFIG. 15C, the display portion 81 b can also obtain similar biologicaldata.

Biological data can be obtained in such a manner that the user executesan application for obtaining and managing biological data, for example.With the application, the electronic device 80 can recognize a touch ofthe finger 60 on the display portion 81 a or the display portion 81 band execute image capturing. Moreover, the above-described biologicaldata can be obtained from the captured image and storage or managementof the data can be executed.

An electronic device 80 a illustrated in FIG. 16 includes a displayportion 81 c in addition to the display portion 81 a and the displayportion 81 b. The display portion 81 c is positioned on the sideopposite to the display portion 81 b with the display portion 81 atherebetween.

As illustrated in FIG. 16, the display portion 81 c is provided in aposition that is naturally touched by at least one of an index finger, amiddle finger, a ring finger, and a little finger of five fingers 60when the user grasps the electronic device 80 a with the hand 60 a. Inaddition, the display portion 81 b is provided in a position that isnaturally touched by a thumb. The display portion 81 b and the displayportion 81 c can each execute fingerprint image capturing. This enablesfingerprint authentication to be executed with multiple fingerprints offingertips and thus is preferable for authentication with higheraccuracy.

Furthermore, the electronic device 80 a has a symmetrical structure,which is preferable because the electronic device can be handled withboth hands, i.e., with either a right hand or a left hand.

Structure Example 2

FIG. 17 is a schematic view of an electronic device 80 b. The electronicdevice 80 b can be used as a tablet terminal. The electronic device 80 bincludes at least a housing 82, a display portion 81 a, and a displayportion 81 b. The display portion 81 a and the display portion 81 binclude a display device of one embodiment of the present invention.

When the hand 60 a of the user is held over or touches the displayportion 81, the electronic device 80 b can execute personalauthentication and obtain biological data of the user.

When the hand 60 a of the user is put on the display portion 81, theelectronic device 80 b can recognize the shape. Then, biological datasuitable for regions corresponding to the respective parts of the hand60 a is obtained. For example, in regions 85 a corresponding tofingertips of the hand 60 a, image capturing of the shapes offingerprints and veins can be executed. In addition, in regions 85 bcorresponding to balls of fingers, image capturing of the shapes ofveins and arterioles can be executed, for example. Moreover, in a region85 c corresponding to a palm, image capturing of a palm print, a vein,an arteriole, and a dermis can be executed, for example. The images ofthe fingerprints, the palm print, and the veins can be used for personalauthentication. Furthermore, the images of the arterioles, the veins,and the dermis can be used to obtain biological data.

When biological data is to be obtained, an image imitating the shape ofa hand may be displayed on the display portion 81 to urge the user toput the hand 60 a on the image. This can improve the recognitionaccuracy of the shape of the hand 60 a.

In this manner, the biological data of the user can be obtained everytime personal authentication for starting up the electronic device 80 bis executed. Thus, the biological data can be accumulated continuouslywith the user being unconscious, which enables continuous healthmanagement to be performed. The above is preferable because the userneed not execute application software or the like for health managementeach time, and obtainment and update of the biological data are notstopped.

Structure Example 3

FIG. 18A is a schematic view of an electronic device 80 c. Theelectronic device 80 c includes a pair of electrodes 83, a camera 84,and a microphone 86 in addition to the components of the electronicdevice 80 b.

The pair of electrodes 83 is provided in parts of the housing 82 withthe display portion 81 a therebetween. The electrodes 83 function aselectrodes for obtaining an electrocardiogram. When the user holds thepair of electrodes 83 with both hands, an electrocardiogram can beobtained. Providing the pair of electrodes 83 in the longitudinaldirection of the housing 82 as illustrated in FIG. 18A enables anelectrocardiogram to be obtained with the user being unconscious whenthe user uses the electronic device 80 c with a landscape screen.

The camera 84 can capture an image of a user's face, for example.Biological data on facial expression, a pupil, complexion, and the likecan be obtained from the image of the user's face.

The microphone 86 can obtain a user's voice. Voiceprint data that can beused for voiceprint authentication can be obtained from the obtainedvoice data. When voice data is regularly obtained and a change in voicequality is monitored, the voice data can be utilized for healthmanagement.

FIG. 18B illustrates an example of a usage state of the electronicdevice 80 c. The display portion 81 a displays data 88 a on anelectrocardiogram obtained by the pair of electrodes 83, data 88 b onthe heart rate, a character image 88 c showing data on the user's healthconditions estimated from a variety of biological data, and the like.

Structure Example of System

With one embodiment of the present invention, a variety of biologicaldata can be obtained regularly and continuously, and such biologicaldata can be utilized for personal authentication or health management.

Examples of biological data that can be obtained using visible light andinfrared light include data on a fingerprint, a palm print, the shape ofa vein, a pulse wave, the respiration rate, a pulse, oxygen saturation,the blood sugar level, the neutral fat concentration, and the like.Other examples include data on facial expression, complexion, a pupil, avoiceprint, and the like. It is preferable to use such a variety ofbiological data to comprehensively determine the user's healthconditions.

As a personal authentication method using biological data, a patternmatching method is typically given. For example, feature values such asthe coordinates of a plurality of characteristic points and a vectorbetween the coordinates of those points are calculated from an image ofa fingerprint, a palm print, the shape of a vein, or the like andcompared with feature values of a user obtained in advance, wherebyauthentication can be performed. When two or more images out of theimages of a fingerprint, a palm print, and the shape of a vein are used,authentication can be executed with high accuracy.

Furthermore, machine learning may be used for personal authenticationusing biological data or determination of health conditions. As alearning model used for machine learning, a learning model in whichlearning has been performed in advance may be used, or a learning modelin which an update is performed using the obtained data on a user may beused. Examples of the machine learning method include supervised machinelearning and unsupervised machine learning

A structure example of a system of one embodiment of the presentinvention and an operation example of the system are described belowwith reference to drawings.

FIG. 19 is a block diagram of a system 90 provided with a display deviceof one embodiment of the present invention. The system 90 includes anarithmetic portion 91, a memory portion 92, an input portion 93, anoutput portion 94, a bus line 95, and the like. The system 90 can beused in a variety of electronic devices including a display portion,such as the above-described electronic device 80.

The arithmetic portion 91 is connected to the memory portion 92, theinput portion 93, the output portion 94, and the like via the bus line95 and has a function of totally controlling these components.

The memory portion 92 has a function of storing data, a program, or thelike. The arithmetic portion 91 reads a program or data from the memoryportion 92 and executes or processes the program or data, wherebyvarious components included in the input portion 93 and the outputportion 94 can be controlled.

As the input portion 93, a variety of sensor devices can be used. Here,a photosensor 93 a, a camera 93 b, a microphone 93 c, anelectrocardiogram monitor 93 d, and the like are illustrated ascomponents included in the input portion 93. As the photosensor 93 a, asensor that uses a light-receiving element included in theabove-described display device can be used. The electrocardiogrammonitor 93 d has a structure including a pair of electrodes formeasuring an electrocardiogram and a measuring device that measures avoltage between the electrodes, a current flowing between theelectrodes, or the like, for example.

The output portion 94 has a function of supplying various data to theuser. Illustrated here is an example including a display 94 a, a speaker94 b, a vibration device 94 c, and the like as components included inthe output portion 94.

Since the display device of one embodiment of the present inventionincludes light-receiving elements functioning as photosensors andlight-emitting elements forming a display portion, the display devicecan serve as both the photosensor 93 a of the input portion 93 and thedisplay 94 a of the output portion 94, which are illustrated in FIG. 19.In other words, the system 90 can be formed by the structure includingthe display device, the arithmetic portion 91, and the memory portion92.

For example, the display device has a function of obtaining biologicaldata on a fingerprint, a palm print, a vein, or the like of a user, andthe arithmetic portion 91 can execute fingerprint authentication, palmprint authentication, or vein authentication on the basis of biologicaldata on the user stored in advance in the memory portion 92 and theobtained biological data.

An example of an operation method of the system of one embodiment of thepresent invention is described below. Here, an operation of executingbiometric authentication is described.

FIG. 20 is a flow chart of the operation method of the system. The flowchart in FIG. 20 includes Step S0 to Step S8.

In Step S0, the operation starts.

In Step S1, whether to execute start-up of the system is determined. Forexample, when power-on of the electronic device, a touch on the displayportion, a change in the attitude of the electronic device, or the likeis sensed, execution of start-up of the system is determined. Incontrast, in the case where they are not sensed, the operation goes toStep S8 and is finished.

In Step S2, whether authentication is necessary is determined. In thecase where authentication has been executed and the system is in alog-in state, it is determined that authentication is unnecessary andthe operation goes to Step S7. In contrast, in the case where it is in alog-off state, it is determined that authentication is necessary and theoperation goes to Step S3.

In Step S3, whether to sense an authentication operation is determined.For example, in the case where a touch of a finger, a palm, or the likeof a user on part of the display portion is sensed, it is determinedthat the authentication operation has been sensed and the operation goesto Step S4. In contrast, in the case where it is not sensed for acertain time, the operation goes to Step S8 and is finished.

In Step S4, authentication data is obtained. For example, an image of afingerprint, a palm print, a vein, or the like of a user is captured,and the obtainment of biological data from the captured image isexecuted.

In Step S5, whether authentication is correctly performed is determined.For example, the data on the fingerprint, the palm print, or the veinobtained in Step S4 and biological data on the user registered inadvance are compared with each other, and whether they match each otheris determined. The determination can be performed by an authenticationmethod that does not use a machine learning model, such as a patternmatching method, or authentication using a machine learning model. Inthe case where authentication is correctly performed, the operation goesto Step S6. In the case where authentication is not performed correctly,the log-off state is maintained and the operation goes back to Step S4.

In Step S6, logging in to the system is executed.

In Step S7, the log-in state is maintained. In the case where the userperforms an end operation or where no input for a certain period issensed, Step S7 is finished and the operation goes to Step S8.

In Step S8, the operation is finished. At least a log-off state is madein Step S8. Furthermore, the state may be a non-energized state, astandby state, or a sleep state. The operation may come back from StepS8 by the operation sensed in Step S1 described above.

Here, in the case where the operation method is applied to theelectronic device 80 illustrated in FIG. 15A or the electronic device 80a illustrated in FIG. 16, sensing of the authentication operation inStep S3 and the obtainment of authentication data in Step S4, which aredescribed above, can be executed by a touch of a fingertip on thedisplay portion 81 b or the display portion 81 c as illustrated in FIG.15A or FIG. 16. Furthermore, as the biological data obtained in Step S4,an image of a fingerprint or the like obtained by image capturing oflight reflected by the fingertip by the light-receiving elementsincluded in the display portion 81 b or the display portion 81 c can beused.

In other words, when a user's finger touches the display portion 81 b orthe display portion 81 c in the electronic device of one embodiment ofthe present invention (e.g., the electronic device 80 or the electronicdevice 80 a), the arithmetic portion 91 can execute fingerprintauthentication with an image of a fingerprint obtained by imagecapturing of light reflected by the finger by the light-receivingelements included in the display portion 81 b or the display portion 81c. Accordingly, the user can unconsciously execute authentication, andan electronic device that is convenient and highly safe can be achieved.

The above is the description of the structure example and the operationexample of the system of one embodiment of the present invention.

[Metal Oxide]

A metal oxide that can be used for the semiconductor layer will bedescribed below.

Note that in this specification and the like, a metal oxide containingnitrogen is also collectively referred to as a metal oxide in somecases. A metal oxide containing nitrogen may be referred to as a metaloxynitride. For example, a metal oxide containing nitrogen, such as zincoxynitride (ZnON), may be used for the semiconductor layer.

Note that in this specification and the like, CAAC (c-axis alignedcrystal) or CAC (Cloud-Aligned Composite) may be stated. CAAC refers toan example of a crystal structure, and CAC refers to an example of afunction or a material composition.

For example, a CAC (Cloud-Aligned Composite)-OS (Oxide Semiconductor)can be used for the semiconductor layer.

A CAC-OS or a CAC-metal oxide has a conducting function in part of thematerial and has an insulating function in another part of the material;as a whole, the CAC-OS or the CAC-metal oxide has a function of asemiconductor. In the case where the CAC-OS or the CAC-metal oxide isused in a semiconductor layer of a transistor, the conducting functionis to allow electrons (or holes) serving as carriers to flow, and theinsulating function is to not allow electrons serving as carriers toflow. By the complementary action of the conducting function and theinsulating function, a switching function (On/Off function) can be givento the CAC-OS or the CAC-metal oxide. In the CAC-OS or the CAC-metaloxide, separation of the functions can maximize each function.

Furthermore, the CAC-OS or the CAC-metal oxide includes conductiveregions and insulating regions. The conductive regions have theabove-described conducting function, and the insulating regions have theabove-described insulating function. Furthermore, in some cases, theconductive regions and the insulating regions in the material areseparated at the nanoparticle level. Furthermore, in some cases, theconductive regions and the insulating regions are unevenly distributedin the material. Furthermore, in some cases, the conductive regions areobserved to be coupled in a cloud-like manner with their boundariesblurred.

Furthermore, in the CAC-OS or the CAC-metal oxide, the conductiveregions and the insulating regions each have a size greater than orequal to 0.5 nm and less than or equal to 10 nm, preferably greater thanor equal to 0.5 nm and less than or equal to 3 nm, and are dispersed inthe material, in some cases.

Furthermore, the CAC-OS or the CAC-metal oxide includes componentshaving different bandgaps. For example, the CAC-OS or the CAC-metaloxide includes a component having a wide gap due to the insulatingregion and a component having a narrow gap due to the conductive region.In the case of the structure, when carriers flow, carriers mainly flowin the component having a narrow gap. Furthermore, the component havinga narrow gap complements the component having a wide gap, and carriersalso flow in the component having a wide gap in conjunction with thecomponent having a narrow gap. Therefore, in the case where theabove-described CAC-OS or CAC-metal oxide is used in a channel formationregion of a transistor, high current driving capability in an on stateof the transistor, that is, a high on-state current and highfield-effect mobility can be obtained.

In other words, the CAC-OS or the CAC-metal oxide can also be referredto as a matrix composite or a metal matrix composite.

Oxide semiconductors (metal oxides) are classified into a single crystaloxide semiconductor and a non-single-crystal oxide semiconductor.Examples of a non-single-crystal oxide semiconductor include a CAAC-OS(c-axis aligned crystalline oxide semiconductor), a polycrystallineoxide semiconductor, an nc-OS (nanocrystalline oxide semiconductor), anamorphous-like oxide semiconductor (a-like OS), and an amorphous oxidesemiconductor.

The CAAC-OS has c-axis alignment, a plurality of nanocrystals areconnected in the a-b plane direction, and its crystal structure hasdistortion. Note that the distortion refers to a portion where thedirection of a lattice arrangement changes between a region with aregular lattice arrangement and another region with a regular latticearrangement in a region where the plurality of nanocrystals areconnected.

The nanocrystal is basically a hexagon but is not always a regularhexagon and is a non-regular hexagon in some cases. Furthermore, apentagonal or heptagonal lattice arrangement, for example, is includedin the distortion in some cases. Note that it is difficult to observe aclear crystal grain boundary (also referred to as grain boundary) evenin the vicinity of distortion in the CAAC-OS. That is, formation of acrystal grain boundary is found to be inhibited by the distortion of alattice arrangement. This is because the CAAC-OS can tolerate distortionowing to a low density of arrangement of oxygen atoms in the a-b planedirection, an interatomic bond length changed by substitution of a metalelement, and the like.

The CAAC-OS tends to have a layered crystal structure (also referred toas a layered structure) in which a layer containing indium and oxygen(hereinafter, In layer) and a layer containing the element M, zinc, andoxygen (hereinafter, (M,Zn) layer) are stacked. Note that indium and theelement Mcan be replaced with each other, and when the element Min the(M,Zn) layer is replaced with indium, the layer can also be referred toas an (In,M,Zn) layer. Furthermore, when indium in the In layer isreplaced with the element M, the layer can be referred to as an (In,M)layer.

The CAAC-OS is a metal oxide with high crystallinity. On the other hand,a clear crystal grain boundary is difficult to observe in the CAAC-OS;thus, it can be said that a reduction in electron mobility due to thecrystal grain boundary is unlikely to occur. Entry of impurities,formation of defects, or the like might decrease the crystallinity of ametal oxide; thus, it can be said that the CAAC-OS is a metal oxide thathas small amounts of impurities and defects (e.g., oxygen vacancies(also referred to as V_(O))). Thus, a metal oxide including a CAAC-OS isphysically stable. Therefore, the metal oxide including a CAAC-OS isresistant to heat and has high reliability.

In the nc-OS, a microscopic region (e.g., a region with a size greaterthan or equal to 1 nm and less than or equal to 10 nm, in particular, aregion with a size greater than or equal to 1 nm and less than or equalto 3 nm) has a periodic atomic arrangement. Furthermore, there is noregularity of crystal orientation between different nanocrystals in thenc-OS. Thus, the orientation in the whole film is not observed.Accordingly, the nc-OS cannot be distinguished from an a-like OS or anamorphous oxide semiconductor by some analysis methods.

Note that indium-gallium-zinc oxide (hereinafter referred to as IGZO),which is a kind of metal oxide containing indium, gallium, and zinc, hasa stable structure in some cases by being formed of the above-describednanocrystals. In particular, crystals of IGZO tend not to grow in theair and thus, a stable structure might be obtained when IGZO is formedof smaller crystals (e.g., the above-described nanocrystals) rather thanlarger crystals (here, crystals with a size of several millimeters orseveral centimeters).

An a-like OS is a metal oxide having a structure between those of thenc-OS and an amorphous oxide semiconductor. The a-like OS includes avoid or a low-density region. That is, the a-like OS has lowcrystallinity as compared with the nc-OS and the CAAC-OS.

An oxide semiconductor (metal oxide) can have various structures thatshow different properties. Two or more of the amorphous oxidesemiconductor, the polycrystalline oxide semiconductor, the a-like OS,the nc-OS, and the CAAC-OS may be included in an oxide semiconductor ofone embodiment of the present invention.

A metal oxide film that functions as a semiconductor layer can bedeposited using either or both of an inert gas and an oxygen gas. Notethat there is no particular limitation on the flow rate ratio of oxygen(the partial pressure of oxygen) at the time of depositing the metaloxide film. However, to obtain a transistor having high field-effectmobility, the flow rate ratio of oxygen (the partial pressure of oxygen)at the time of depositing the metal oxide film is preferably higher thanor equal to 0% and lower than or equal to 30%, further preferably higherthan or equal to 5% and lower than or equal to 30%, and still furtherpreferably higher than or equal to 7% and lower than or equal to 15%.

The energy gap of the metal oxide is preferably 2 eV or more, furtherpreferably 2.5 eV or more, still further preferably 3 eV or more. Withthe use of a metal oxide having such a wide energy gap, the off-statecurrent of the transistor can be reduced.

The substrate temperature during the deposition of the metal oxide filmis preferably lower than or equal to 350° C., further preferably higherthan or equal to room temperature and lower than or equal to 200° C.,and still further preferably higher than or equal to room temperatureand lower than or equal to 130° C. The substrate temperature during thedeposition of the metal oxide film is preferably room temperaturebecause productivity can be increased.

The metal oxide film can be formed by a sputtering method.Alternatively, a PLD method, a PECVD method, a thermal CVD method, anALD method, or a vacuum evaporation method, for example, may be used.

The above is the description of the metal oxide.

At least part of this embodiment can be implemented in combination withthe other embodiments described in this specification as appropriate.

Embodiment 2

In this embodiment, a display device of one embodiment of the presentinvention will be described with reference to FIG. 21A and FIG. 21B.

A display device of one embodiment of the present invention includesfirst pixel circuits including a light-receiving element and secondpixel circuits including a light-emitting element. The first pixelcircuits and the second pixel circuits are each arranged in a matrix.

FIG. 21A illustrates an example of the first pixel circuit including alight-receiving element. FIG. 21B illustrates an example of the secondpixel circuit including a light-emitting element.

A pixel circuit PIX1 illustrated in FIG. 21A includes a light-receivingelement PD, a transistor M1, a transistor M2, a transistor M3, atransistor M4, and a capacitor C1. Here, an example in which aphotodiode is used as the light-receiving element PD is illustrated.

A cathode of the light-receiving element PD is electrically connected toa wiring V1, and an anode thereof is electrically connected to one of asource and a drain of the transistor M1. A gate of the transistor M1 iselectrically connected to a wiring TX, and the other of the source andthe drain thereof is electrically connected to one electrode of thecapacitor C1, one of a source and a drain of the transistor M2, and agate of the transistor M3. A gate of the transistor M2 is electricallyconnected to a wiring RES, and the other of the source and the drainthereof is electrically connected to a wiring V2. One of a source and adrain of the transistor M3 is electrically connected to a wiring V3, andthe other of the source and the drain thereof is electrically connectedto one of a source and a drain of the transistor M4. A gate of thetransistor M4 is electrically connected to a wiring SE, and the other ofthe source and the drain thereof is electrically connected to a wiringOUT1.

A constant potential is supplied to the wiring V1, the wiring V2, andthe wiring V3. When the light-receiving element PD is driven with areverse bias, a potential lower than the potential of the wiring V1 issupplied to the wiring V2. The transistor M2 is controlled by a signalsupplied to the wiring RES and has a function of resetting the potentialof a node connected to the gate of the transistor M3 to a potentialsupplied to the wiring V2. The transistor M1 is controlled by a signalsupplied to the wiring TX and has a function of controlling the timingat which the potential of the node changes, in accordance with a currentflowing through the light-receiving element PD. The transistor M3functions as an amplifier transistor for performing output in responseto the potential of the node. The transistor M4 is controlled by asignal supplied to the wiring SE and functions as a selection transistorfor reading an output corresponding to the potential of the node by anexternal circuit connected to the wiring OUT1.

A pixel circuit PIX2 illustrated in FIG. 21B includes a light-emittingelement EL, a transistor M5, a transistor M6, a transistor M7, and acapacitor C2. Here, an example in which a light-emitting diode is usedas the light-emitting element EL is illustrated. In particular, anorganic EL element is preferably used as the light-emitting element EL.

A gate of the transistor M5 is electrically connected to a wiring VG,one of a source and a drain thereof is electrically connected to awiring VS, and the other of the source and the drain thereof iselectrically connected to one electrode of the capacitor C2 and a gateof the transistor M6. One of a source and a drain of the transistor M6is electrically connected to a wiring V4, and the other thereof iselectrically connected to an anode of the light-emitting element EL andone of a source and a drain of the transistor M7. A gate of thetransistor M7 is electrically connected to a wiring MS, and the other ofthe source and the drain thereof is electrically connected to a wiringOUT2. A cathode of the light-emitting element EL is electricallyconnected to a wiring V5.

A constant potential is supplied to the wiring V4 and the wiring V5. Inthe light-emitting element EL, the anode side can have a high potentialand the cathode side can have a lower potential than the anode side. Thetransistor M5 is controlled by a signal supplied to the wiring VG andfunctions as a selection transistor for controlling a selection state ofthe pixel circuit PIX2. The transistor M6 functions as a drivingtransistor that controls a current flowing through the light-emittingelement EL, in accordance with a potential supplied to the gate. Whenthe transistor M5 is in an on state, a potential supplied to the wiringVS is supplied to the gate of the transistor M6, and the emissionluminance of the light-emitting element EL can be controlled inaccordance with the potential. The transistor M7 is controlled by asignal supplied to the wiring MS and has a function of outputting apotential between the transistor M6 and the light-emitting element EL tothe outside through the wiring OUT2.

Note that in the display device of this embodiment, the light-emittingelement may be made to emit light in a pulsed manner so as to display animage. A reduction in the driving time of the light-emitting element canreduce the power consumption of the display device and suppress heatgeneration of the display device. An organic EL element is particularlypreferable because of its favorable frequency characteristics. Thefrequency can be higher than or equal to 1 kHz and lower than or equalto 100 MHz, for example.

Here, a transistor using a metal oxide (an oxide semiconductor) in asemiconductor layer where a channel is formed is preferably used as thetransistor M1, the transistor M2, the transistor M3, and the transistorM4 included in the pixel circuit PIX1 and the transistor M5, thetransistor M6, and the transistor M7 included in the pixel circuit PIX2.

A transistor using a metal oxide having a wider band gap and a lowercarrier density than silicon can achieve an extremely low off-statecurrent. Thus, such a low off-state current enables retention of chargeaccumulated in a capacitor that is connected in series with thetransistor for a longtime. Therefore, it is particularly preferable touse a transistor using an oxide semiconductor as the transistor M1, thetransistor M2, and the transistor M5 each of which is connected inseries with the capacitor C1 or the capacitor C2. Moreover, the use oftransistors using an oxide semiconductor as the other transistors canreduce the manufacturing cost.

Alternatively, transistors using silicon as a semiconductor in which achannel is formed can be used as the transistor M1 to the transistor M7.In particular, the use of silicon with high crystallinity, such assingle crystal silicon or polycrystalline silicon, is preferable becausehigh field-effect mobility is achieved and higher-speed operation ispossible.

Alternatively, a transistor using an oxide semiconductor may be used asone or more of the transistor M1 to the transistor M7, and transistorsusing silicon may be used as the other transistors.

Although n-channel transistors are shown as the transistors in FIG. 21Aand FIG. 21B, p-channel transistors can alternatively be used.

The transistors included in the pixel circuit PIX1 and the transistorsincluded in the pixel circuit PIX2 are preferably formed side by sideover the same substrate. It is particularly preferable that thetransistors included in the pixel circuit PIX1 and the transistorsincluded in the pixel circuit PIX2 be periodically arranged in oneregion.

One or more layers including one or both of the transistor and thecapacitor are preferably provided to overlap with the light-receivingelement PD or the light-emitting element EL. Thus, the effective area ofeach pixel circuit can be reduced, and a high-resolution light-receivingportion or display portion can be achieved.

At least part of this embodiment can be implemented in combination withthe other embodiments described in this specification as appropriate.

Embodiment 3

In this embodiment, electronic devices of one embodiment of the presentinvention will be described with reference to FIG. 22 to FIG. 24.

An electronic device in this embodiment includes a display device of oneembodiment of the present invention. For example, the display device ofone embodiment of the present invention can be used in a display portionof the electronic device. The display device of one embodiment of thepresent invention has a function of sensing light, and thus can performbiometric authentication on the display portion or sense a touch or anear touch on the display portion. Thus, the electronic device can haveimproved functionality and convenience, for example.

Examples of the electronic devices include a digital camera, a digitalvideo camera, a digital photo frame, a mobile phone, a portable gameconsole, a portable information terminal, and an audio reproducingdevice, in addition to electronic devices with a relatively largescreen, such as a television device, a desktop or laptop personalcomputer, a monitor of a computer or the like, digital signage, and alarge game machine such as a pachinko machine.

The electronic device in this embodiment may include a sensor (a sensorhaving a function of measuring force, displacement, position, speed,acceleration, angular velocity, rotational frequency, distance, light,liquid, magnetism, temperature, a chemical substance, sound, time,hardness, electric field, current, voltage, electric power, radiation,flow rate, humidity, gradient, oscillation, a smell, or infrared rays).

The electronic device in this embodiment can have a variety offunctions. For example, the electronic device can have a function ofdisplaying a variety of data (a still image, a moving image, a textimage, and the like) on the display portion, a touch panel function, afunction of displaying a calendar, date, time, and the like, a functionof executing a variety of software (programs), a wireless communicationfunction, and a function of reading out a program or data stored in arecording medium.

An electronic device 6500 illustrated in FIG. 22A is a portableinformation terminal that can be used as a smartphone.

The electronic device 6500 includes a housing 6501, a display portion6502, a power button 6503, buttons 6504, a speaker 6505, a microphone6506, a camera 6507, a light source 6508, and the like. The displayportion 6502 has a touch panel function.

The display device of one embodiment of the present invention can beused in the display portion 6502.

FIG. 22B is a schematic cross-sectional view including an end portion ofthe housing 6501 on the microphone 6506 side.

A protection member 6510 having a light-transmitting property isprovided on the display surface side of the housing 6501, and a displaypanel 6511, an optical member 6512, a touch sensor panel 6513, a printedcircuit board 6517, a battery 6518, and the like are provided in a spacesurrounded by the housing 6501 and the protection member 6510.

The display panel 6511, the optical member 6512, and the touch sensorpanel 6513 are fixed to the protection member 6510 with an adhesivelayer (not shown).

Part of the display panel 6511 is folded back in a region outside thedisplay portion 6502, and an FPC 6515 is connected to the part that isfolded back. An IC 6516 is mounted on the FPC 6515. The FPC 6515 isconnected to a terminal provided on the printed circuit board 6517.

A flexible display of one embodiment of the present invention can beused as the display panel 6511. Thus, an extremely lightweightelectronic device can be achieved. Since the display panel 6511 isextremely thin, the battery 6518 with high capacity can be mounted withthe thickness of the electronic device controlled. An electronic devicewith a narrow frame can be achieved when part of the display panel 6511is folded back so that the portion connected to the FPC 6515 is providedon the rear side of a pixel portion.

FIG. 23A illustrates an example of a television device. In a televisiondevice 7100, a display portion 7000 is incorporated in a housing 7101.Here, a structure in which the housing 7101 is supported by a stand 7103is illustrated.

A display device of one embodiment of the present invention can be usedin the display portion 7000.

Operation of the television device 7100 illustrated in FIG. 23A can beperformed with an operation switch provided in the housing 7101 or aseparate remote controller 7111. Alternatively, the display portion 7000may include a touch sensor, and the television device 7100 may beoperated by a touch on the display portion 7000 with a finger or thelike. The remote controller 7111 may be provided with a display portionfor displaying data output from the remote controller 7111. Withoperation keys or a touch panel provided in the remote controller 7111,channels and volume can be operated and videos displayed on the displayportion 7000 can be operated.

Note that the television device 7100 has a structure in which areceiver, a modem, and the like are provided. A general televisionbroadcast can be received with the receiver. When the television deviceis connected to a communication network with or without wires via themodem, one-way (from a transmitter to a receiver) or two-way (between atransmitter and a receiver or between receivers, for example) datacommunication can be performed.

FIG. 23B illustrates an example of a laptop personal computer. A laptoppersonal computer 7200 includes a housing 7211, a keyboard 7212, apointing device 7213, an external connection port 7214, and the like. Inthe housing 7211, the display portion 7000 is incorporated.

The display device of one embodiment of the present invention can beused in the display portion 7000.

FIG. 23C and FIG. 23D illustrate examples of digital signage.

Digital signage 7300 illustrated in FIG. 23C includes a housing 7301,the display portion 7000, a speaker 7303, and the like. Furthermore, thedigital signage can include an LED lamp, operation keys (including apower switch or an operation switch), a connection terminal, a varietyof sensors, a microphone, and the like.

FIG. 23D is digital signage 7400 attached to a cylindrical pillar 7401.The digital signage 7400 includes the display portion 7000 providedalong a curved surface of the pillar 7401.

The display device of one embodiment of the present invention can beused for the display portion 7000 in FIG. 23C and FIG. 23D.

A larger area of the display portion 7000 can increase the amount ofdata that can be provided at a time. The larger display portion 7000attracts more attention, so that the advertising effectiveness can beenhanced, for example.

The use of a touch panel in the display portion 7000 is preferablebecause in addition to display of a still image or a moving image on thedisplay portion 7000, intuitive operation by a user is possible.Moreover, for an application for providing information such as routeinformation or traffic information, usability can be enhanced byintuitive operation.

As illustrated in FIG. 23C and FIG. 23D, the digital signage 7300 or thedigital signage 7400 is preferably capable of working with aninformation terminal 7311 or an information terminal 7411 such as auser's smartphone through wireless communication. For example,information of an advertisement displayed on the display portion 7000can be displayed on a screen of the information terminal 7311 or theinformation terminal 7411. By operation of the information terminal 7311or the information terminal 7411, display on the display portion 7000can be switched.

It is possible to make the digital signage 7300 or the digital signage7400 execute a game with use of the screen of the information terminal7311 or the information terminal 7411 as an operation means(controller). Thus, an unspecified number of users can join in and enjoythe game concurrently.

Electronic devices illustrated in FIG. 24A to FIG. 24F include a housing9000, a display portion 9001, a speaker 9003, an operation key 9005(including a power switch or an operation switch), a connection terminal9006, a sensor 9007 (a sensor having a function of measuring force,displacement, position, speed, acceleration, angular velocity,rotational frequency, distance, light, liquid, magnetism, temperature, achemical substance, sound, time, hardness, electric field, current,voltage, electric power, radiation, flow rate, humidity, gradient,oscillation, a smell, or infrared rays), a microphone 9008, and thelike.

The electronic devices illustrated in FIG. 24A to FIG. 24F have avariety of functions. For example, the electronic devices can have afunction of displaying a variety of information (a still image, a movingimage, a text image, and the like) on the display portion, a touch panelfunction, a function of displaying a calendar, date, time, and the like,a function of controlling processing with use of a variety of software(programs), a wireless communication function, and a function of readingout and processing a program or data stored in a recording medium. Notethat the functions of the electronic devices are not limited thereto,and the electronic devices can have a variety of functions. Theelectronic devices may include a plurality of display portions. Theelectronic devices may each include a camera or the like and have afunction of taking a still image or a moving image and storing the takenimage in a recording medium (an external recording medium or a recordingmedium incorporated in the camera), a function of displaying the takenimage on the display portion, or the like.

The details of the electronic devices illustrated in FIG. 24A to FIG.24F are described below.

FIG. 24A is a perspective view illustrating a portable informationterminal 9101. For example, the portable information terminal 9101 canbe used as a smartphone. Note that the portable information terminal9101 may be provided with the speaker 9003, the connection terminal9006, the sensor 9007, or the like. The portable information terminal9101 can display characters and image information on its plurality ofsurfaces. FIG. 24A shows an example where three icons 9050 aredisplayed. Information 9051 indicated by dashed rectangles can bedisplayed on another surface of the display portion 9001. Examples ofthe information 9051 include notification of reception of an e-mail,SNS, or an incoming call, the title and sender of an e-mail, SNS, or thelike, the date, the time, remaining battery, and the reception strengthof an antenna. Alternatively, the icon 9050 or the like may be displayedin the position where the information 9051 is displayed.

FIG. 24B is a perspective view illustrating a portable informationterminal 9102. The portable information terminal 9102 has a function ofdisplaying information on three or more surfaces of the display portion9001. Here, an example in which information 9052, information 9053, andinformation 9054 are displayed on different surfaces is shown. Forexample, a user can check the information 9053 displayed in a positionthat can be observed from above the portable information terminal 9102,with the portable information terminal 9102 put in a breast pocket ofhis/her clothes. The user can seethe display without taking out theportable information terminal 9102 from the pocket and decide whether toanswer the call, for example.

FIG. 24C is a perspective view illustrating a watch-type portableinformation terminal 9200. The display surface of the display portion9001 is curved and provided, and display can be performed along thecurved display surface. Mutual communication between the portableinformation terminal 9200 and, for example, a headset capable ofwireless communication enables hands-free calling. With the connectionterminal 9006, the portable information terminal 9200 can perform mutualdata transmission with another information terminal and charging. Notethat the charging operation may be performed by wireless power feeding.

FIG. 24D, FIG. 24E, and FIG. 24F are perspective views illustrating afoldable portable information terminal 9201. FIG. 24D is a perspectiveview of an opened state of the portable information terminal 9201, FIG.24F is a perspective view of a folded state thereof, and FIG. 24E is aperspective view of a state in the middle of change from one of FIG. 24Dand FIG. 24F to the other. The portable information terminal 9201 ishighly portable in the folded state and is highly browsable in theopened state because of a seamless large display region. The displayportion 9001 of the portable information terminal 9201 is supported bythree housings 9000 joined by hinges 9055. For example, the displayportion 9001 can be curved with a radius of curvature greater than orequal to 0.1 mm and less than or equal to 150 mm.

At least part of this embodiment can be implemented in combination withthe other embodiments described in this specification as appropriate.

REFERENCE NUMERALS

10A to 10F: display devices, 21, 22, 23 a, 23 c: light, 23 b, 23 d:reflected light, 30, 31B, 31G, 31R, 31W, 32: pixels, 40, 40 a, 40 b, 40c, 40 d: curved portions, 41, 42: transistors, 50, 50 a to 50 n: displaydevices, 51, 51 a, 51 b, 52: substrates, 53: light-receiving element,54: light-emitting element, 55, 55 a, 55 b: functional layer, 56:support member, 57, 57B, 57G, 57R: light-emitting elements, 58:reflective layer, 59, 59 a to 59 g: light guide plate, 60: finger, 60 a:hand, 61: contact portion, 62: fingerprint, 63: image-capturing range,65: stylus, 66: path, 67: a blood vessel, 71: resin layer, 72:conductive layer, 80, 80 a to 80 c: electronic device, 81, 81 a to 81 c:display portions, 82: housing, 83: electrode, 84: camera, 85 a to 85 c:regions, 86: microphone, 88 a: data, 88 b: data, 88 c: character image,90: system, 91: arithmetic portion, 92: memory portion, 93: inputportion, 93 a: photosensor, 93 b: camera, 93 c: microphone, 93 d:electrocardiogram monitor, 94: output portion, 94 a: display, 94 b:speaker, 94 c: vibration device, 95: bus line

1. A display device comprising a first substrate, a light guide plate, a plurality of first light-emitting elements, a second light-emitting element, and a plurality of light-receiving elements, wherein the light guide plate comprises a first portion having a first surface and a second portion having a second surface that connects with the first surface and has a different normal direction from the first surface, wherein an area of the second surface is smaller than an area of the first surface, wherein the first substrate comprises a third portion provided along the first portion of the light guide plate and a fourth portion provided along the second portion, wherein the first light-emitting elements and the light-receiving elements are provided between the first substrate and the light guide plate, wherein the first light-emitting elements emit first light through the light guide plate, wherein the second light-emitting element emits second light to a side surface of the light guide plate, wherein the light-receiving elements receive the second light and converting the second light to an electric signal, wherein the first light includes visible light, and wherein the second light includes infrared light.
 2. The display device according to claim 1, wherein the first surface and the second surface each have a flat surface, wherein the light guide plate comprises a curved portion between the first portion and the second portion, and wherein an angle formed between the first surface and the second surface is greater than 0 degrees and less than or equal to 90 degrees.
 3. The display device according to claim 1, wherein the second surface comprises a curved surface, and wherein the first portion and the second portion are provided to connect with each other in the light guide plate.
 4. The display device according to claim 3, wherein the second surface comprises the curved surface curved at an angle of greater than or equal to 90 degrees and less than or equal to 180 degrees.
 5. The display device according to claim 1, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the first portion side of the light guide plate.
 6. The display device according to claim 1, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the second portion side of the light guide plate.
 7. The display device according to claim 1, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a first electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and a second electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, and wherein the first pixel electrode and the second pixel electrode are provided over a same surface.
 8. The display device according to claim 1, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the active layer therebetween.
 9. The display device according to claim 1, wherein the first light-emitting elements each comprise a first pixel electrode, a common layer, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, the common layer, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, wherein the common layer comprises a portion overlapping with the first pixel electrode and the light-emitting layer and a portion overlapping with the second pixel electrode and the active layer, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the common layer and the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the common layer and the active layer therebetween.
 10. An electronic device comprising a housing, a display portion, and an arithmetic portion, wherein the display portion comprises a first portion provided along a surface of the housing and a second portion provided along another surface of the housing, wherein the second portion comprises a region whose surface has a different normal direction from a surface of the first portion, wherein the second portion comprises a light-receiving element, and wherein the arithmetic portion has a function of executing, when a finger of a user touches the second portion, fingerprint authentication with an image of a fingerprint obtained by image capturing of light reflected by the finger by the light-receiving element.
 11. The display device according to claim 2, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the first portion side of the light guide plate.
 12. The display device according to claim 3, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the first portion side of the light guide plate.
 13. The display device according to claim 4, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the first portion side of the light guide plate.
 14. The display device according to claim 2, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the second portion side of the light guide plate.
 15. The display device according to claim 3, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the second portion side of the light guide plate.
 16. The display device according to claim 4, wherein the second light-emitting element is provided so as to emit the second light to the side surface positioned in an end portion on the second portion side of the light guide plate.
 17. The display device according to claim 2, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a first electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and a second electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, and wherein the first pixel electrode and the second pixel electrode are provided over a same surface.
 18. The display device according to claim 3, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a first electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and a second electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, and wherein the first pixel electrode and the second pixel electrode are provided over a same surface.
 19. The display device according to claim 4, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a first electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and a second electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, and wherein the first pixel electrode and the second pixel electrode are provided over a same surface.
 20. The display device according to claim 5, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a first electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and a second electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, and wherein the first pixel electrode and the second pixel electrode are provided over a same surface.
 21. The display device according to claim 6, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a first electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and a second electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, and wherein the first pixel electrode and the second pixel electrode are provided over a same surface.
 22. The display device according to claim 2, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the active layer therebetween.
 23. The display device according to claim 3, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the active layer therebetween.
 24. The display device according to claim 4, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the active layer therebetween.
 25. The display device according to claim 5, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the active layer therebetween.
 26. The display device according to claim 6, wherein the first light-emitting elements each comprise a first pixel electrode, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the active layer therebetween.
 27. The display device according to claim 2, wherein the first light-emitting elements each comprise a first pixel electrode, a common layer, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, the common layer, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, wherein the common layer comprises a portion overlapping with the first pixel electrode and the light-emitting layer and a portion overlapping with the second pixel electrode and the active layer, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the common layer and the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the common layer and the active layer therebetween.
 28. The display device according to claim 3, wherein the first light-emitting elements each comprise a first pixel electrode, a common layer, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, the common layer, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, wherein the common layer comprises a portion overlapping with the first pixel electrode and the light-emitting layer and a portion overlapping with the second pixel electrode and the active layer, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the common layer and the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the common layer and the active layer therebetween.
 29. The display device according to claim 4, wherein the first light-emitting elements each comprise a first pixel electrode, a common layer, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, the common layer, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, wherein the common layer comprises a portion overlapping with the first pixel electrode and the light-emitting layer and a portion overlapping with the second pixel electrode and the active layer, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the common layer and the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the common layer and the active layer therebetween.
 30. The display device according to claim 5, wherein the first light-emitting elements each comprise a first pixel electrode, a common layer, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, the common layer, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, wherein the common layer comprises a portion overlapping with the first pixel electrode and the light-emitting layer and a portion overlapping with the second pixel electrode and the active layer, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the common layer and the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the common layer and the active layer therebetween.
 31. The display device according to claim 6, wherein the first light-emitting elements each comprise a first pixel electrode, a common layer, a light-emitting layer, and a common electrode, wherein the light-receiving elements each comprise a second pixel electrode, the common layer, an active layer, and the common electrode, wherein the light-emitting layer and the active layer include different organic compounds from each other, wherein the first pixel electrode and the second pixel electrode are provided over a same surface, wherein the common layer comprises a portion overlapping with the first pixel electrode and the light-emitting layer and a portion overlapping with the second pixel electrode and the active layer, and wherein the common electrode comprises a portion overlapping with the first pixel electrode with the common layer and the light-emitting layer therebetween and a portion overlapping with the second pixel electrode with the common layer and the active layer therebetween. 